Please note that not all hardware/OS combinations are supported. Determine your platform, OS version and Python version before referencing the table below.
Depending on your OS, Concrete-ML may be installed with Docker or with pip:
OS / HW
Available on Docker
Available on pip
Also, only some versions of python are supported: in the current release, these are 3.7 (linux only), 3.8 and 3.9.
Most of these limits are shared with the rest of the Concrete stack (namely Concrete-Numpy and Concrete-Compiler). Support for more platforms will be added in the future.
Using PyPi
Requirements
Installing Concrete-ML using PyPi requires a Linux-based OS or macOS running on an x86 CPU. For Apple Silicon, Docker is the only currently supported option (see ).
Installing on Windows can be done using Docker or WSL. On WSL, Concrete-ML will work as long as the package is not installed in the /mnt/c/ directory, which corresponds to the host OS filesystem.
Installation
To install Concrete-ML from PyPi, run the following:
This will automatically install all dependencies, notably Concrete-Numpy.
Using Docker
Concrete-ML can be installed using Docker by either pulling the latest image or a specific version:
The image can be used with Docker volumes, .
The image can then be used via the following command:
This will launch a Concrete-ML enabled Jupyter server in Docker that can be accessed directly from a browser.
Alternatively, a shell can be lauched in Docker, with or without volumes:
Support and Issues
Concrete-ML is a constant work-in-progress, and thus may contain bugs or suboptimal APIs.
Before opening an issue or asking for support, please read this documentation to understand common issues and limitations of Concrete-ML. You can also check the outstanding issues on github.
Furthermore, undefined behavior may occur if the input-set, which is internally used by the compilation core to set bit-widths of some intermediate data, is not sufficiently representative of the future user inputs. With all the inputs in the input-set, it appears that intermediate data can be represented as an n-bit integer. But, for a particular computation, this same intermediate data needs additional bits to be represented. The FHE execution for this computation will result in an incorrect output, as typically occurs in integer overflows in classical programs.
If you didn't find an answer, you can ask a question on the Zama forum, or in the FHE.org discord.
Submitting an issue
When submitting an issue (), ideally include as much information as possible. In addition to the Python script, the following information is useful:
the reproducibility rate you see on your side
any insight you might have on the bug
any workaround you have been able to find
If you would like to contribute to project and send pull requests, take a look at the guide.
concrete.ml.common.debugging
module concrete.ml.common.debugging
Module for debugging.
Global Variables
custom_assert
concrete.ml.onnx
module concrete.ml.onnx
ONNX module.
Global Variables
onnx_impl_utils
ops_impl
onnx_utils
Documentation
Using GitBook
Documentation with GitBook is done mainly by pushing content on GitHub. GitBook then pulls the docs from the repository and publishes. In most cases, GitBook is just a mirror of what is available in GitHub.
There are, however, some use-cases where documentation can be modified directly in GitBook (and then, push the modifications to GitHub), for example when the documentation is modified by a person outside of Zama. In this case, a GitHub branch is created, and a GitHub space is associated to it: modifications are done in this space and automatically pushed to the branch. Once the modifications are done, one can simply create a pull-request, to finally merge modifications on the main branch.
docker pull zamafhe/concrete-ml:latest
# or
docker pull zamafhe/concrete-ml:v0.4.0
# Without local volume:
docker run --rm -it -p 8888:8888 zamafhe/concrete-ml
# With local volume to save notebooks on host:
docker run --rm -it -p 8888:8888 -v /host/path:/data zamafhe/concrete-ml
docker run --rm -it zamafhe/concrete-ml /bin/bash
make docs_and_open
convert
onnx_model_manipulations
Global Variables
protocols
tree_to_numpy
base
torch_module
glm
linear_model
qnn
rf
svm
tree
xgb
Global Variables
fhe_client_server
Global Variables
quantizers
base_quantized_op
quantized_module
post_training
quantized_ops
Deep Learning Examples
Summary
The following table summarizes the examples in this section:
Model
Data-set
Metric
Floating Point
Simulation
FHE
Examples
concrete.ml.torch
module concrete.ml.torch
Modules for torch to numpy conversion.
Global Variables
numpy_module
concrete.ml.common.debugging.custom_assert
module concrete.ml.common.debugging.custom_assert
Provide some variants of assert.
concrete.ml.common.utils
module concrete.ml.common.utils
Utils that can be re-used by other pieces of code in the module.
Advanced Features
Concrete-ML offers some features for advanced users that wish to adjust the cryptographic parameters that are generated by the Concrete stack for a certain machine learning model.
Approximate computations using the p_error parameter
Concrete-ML makes use of table lookup (TLU) to represent any non-linear operation (e.g. sigmoid). This TLU is implemented through the Programmable Bootstrapping (PBS) operation which will apply a non-linear operation in the cryptographic realm.
concrete.ml.sklearn.tree_to_numpy
module concrete.ml.sklearn.tree_to_numpy
Implements the conversion of a tree model to a numpy function.
Set Up Docker
Before you start this section, you must install Docker by following official guide.
Building the image
Once you have access to this repository and the dev environment is installed on your host OS (via make setup_env once ), you should be able to launch the commands to build the dev Docker image with make docker_build.
make docker_start
# or build and start at the same time
make docker_build_and_start
# or equivalently but shorter
make docker_bas
function assert_true
Provide a custom assert to check that the condition is True.
Args:
condition (bool): the condition. If False, raise AssertionError
on_error_msg (str): optional message for precising the error, in case of error
error_type (Type[Exception]): the type of error to raise, if condition is not fulfilled. Default to AssertionError
function assert_false
Provide a custom assert to check that the condition is False.
Args:
condition (bool): the condition. If True, raise AssertionError
on_error_msg (str): optional message for precising the error, in case of error
error_type (Type[Exception]): the type of error to raise, if condition is not fulfilled. Default to AssertionError
function assert_not_reached
Provide a custom assert to check that a piece of code is never reached.
Args:
on_error_msg (str): message for precising the error
error_type (Type[Exception]): the type of error to raise, if condition is not fulfilled. Default to AssertionError
Global Variables
DEFAULT_P_ERROR_PBS
function replace_invalid_arg_name_chars
Sanitize arg_name, replacing invalid chars by _.
This does not check that the starting character of arg_name is valid.
Args:
arg_name (str): the arg name to sanitize.
Returns:
str: the sanitized arg name, with only chars in _VALID_ARG_CHARS.
function generate_proxy_function
Generate a proxy function for a function accepting only *args type arguments.
This returns a runtime compiled function with the sanitized argument names passed in desired_functions_arg_names as the arguments to the function.
Args:
function_to_proxy (Callable): the function defined like def f(*args) for which to return a function like f_proxy(arg_1, arg_2) for any number of arguments.
desired_functions_arg_names (Iterable[str]): the argument names to use, these names are sanitized and the mapping between the original argument name to the sanitized one is returned in a dictionary. Only the sanitized names will work for a call to the proxy function.
Returns:
Tuple[Callable, Dict[str, str]]: the proxy function and the mapping of the original arg name to the new and sanitized arg names.
function get_onnx_opset_version
Return the ONNX opset_version.
Args:
onnx_model (onnx.ModelProto): the model.
Returns:
int: the version of the model
In Concrete-ML, the result of the TLU operation is obtained with a specific error probability:
A single PBS operation has 1 - DEFAULT_P_ERROR_PBS = 99.9936657516% chances of being correct. This number plays a role in the cryptographic parameters. As such, the lower the p_error, the more constraining the parameters will become. This has an impact on both key generation and, more importantly, on FHE execution time.
This number is set by default to be relatively low such that any user can build deep circuits without being impacted by this noise as described in the concepts section. However, there might be use cases and specific circuits where the Gaussian noise can increase without being too dramatic for the circuit accuracy. In that case, increasing the p_error can be relevant as it will reduce the execution time in FHE.
Here is a visualization of the effect of the p_error over a simple linear regression with a p_error = 0.1 vs the default p_error value:
Impact of p_error in a Linear Regression
The execution for the two models are 336 ms per example for the standard p_error and 253 ms per example for a p_error = 0.1 (on a 8 cores Intel CPU machine). Obviously, this speedup is very dependent on model complexity. To obtain a speedup while maintaining good accuracy, it is possible to search for a good value of p_error. Currently no heuristic has been proposed to find a good value a-priori.
Users have the possibility to change this p_error as they choose fit, by passing an argument to the compile function of any of the models. Here is an example:
DEFAULT_P_ERROR_PBS = 6.3342483999973e-05
Global Variables
MAXIMUM_TLU_BIT_WIDTH
OPSET_VERSION_FOR_ONNX_EXPORT
EXPECTED_NUMBER_OF_OUTPUTS_PER_TASK
function tree_to_numpy
Convert the tree inference to a numpy functions using Hummingbird.
Args:
model (onnx.ModelProto): The model to convert.
x (numpy.ndarray): The input data.
framework (str): The framework from which the onnx_model is generated.
(options: 'xgboost', 'sklearn')
task (Task): The task the model is solving
output_n_bits (int): The number of bits of the output.
Returns:
Tuple[Callable, List[QuantizedArray], onnx.ModelProto]: A tuple with a function that takes a numpy array and returns a numpy array, QuantizedArray object to quantize and dequantize the output of the tree, and the ONNX model.
Concrete-ML is an open-source privacy-preserving machine learning inference framework based on fully homomorphic encryption (FHE). It enables data scientists without any prior knowledge of cryptography to automatically turn machine learning models into their FHE equivalent, using familiar APIs from Scikit-learn and PyTorch (see how it looks for linear models, tree-based models and neural networks).
Fully Homomorphic Encryption (FHE) is an encryption technique that allows computing directly on encrypted data, without needing to decrypt it. With FHE, you can build private-by-design applications without compromising on features. You can learn more about FHE in this introduction, or by joining the FHE.org community.
Example usage
Here is a simple example of classification on encrypted data using logistic regression. More examples can be found .
This example shows the typical flow of a Concrete-ML model:
The model is trained on unencrypted (plaintext) data using scikit-learn. As FHE operates over integers, Concrete-ML quantizes the model to use only integers during inference.
The quantized model is compiled to a FHE equivalent. Under the hood, the model is first converted to a Concrete-Numpy program, then compiled.
Inference can then be done on encrypted data. The above example shows encrypted inference in the model development phase. Alternatively, in in a client/server setting, the data is encrypted by the client, processed securely by the server and then decrypted by the client.
Current limitations
To make a model work with FHE, the only constraint is to make it run within the supported precision limitations of Concrete-ML (currently 8-bit integers). Thus, machine learning models are required to be quantized, which sometimes leads to a loss of accuracy versus the original model operating on plaintext.
Additionally, Concrete-ML currently only supports FHE inference. On the other hand, training has to be done on unencrypted data, producing a model which is then converted to a FHE equivalent that can perform encrypted inference, i.e. prediction over encrypted data.
Finally, in Concrete-ML there is currently no support for pre-processing model inputs and for post-processing model outputs. These processing stages may involve text to numerical feature transformation, dimensionality reduction, KNN or clustering, featurization, normalization, and the mixing of results of ensemble models.
All of these issues are currently being addressed and significant improvements are expected to be released in the coming months.
Concrete Stack
Concrete-ML is built on top of Zama's Concrete framework. It uses , which itself uses the and the . To use these libraries directly, refer to the and documentations.
Online demos and tutorials.
Various tutorials are proposed for the and for . In addition, we also list standalone use-cases:
: a Python and notebook showing a Quantization Aware Training (done with and following constraints of the package) and its corresponding use in Concrete-ML.
: a notebook, which gives a solution to the . Done with XGBoost from Concrete-ML. It comes as a companion of , and was the subject of a blogpost in .
More generally, if you have built awesome projects using Concrete-ML, feel free to let us know and we'll link to it!
Additional resources
Looking for support? Ask our team!
Support forum: (we answer in less than 24 hours).
Live discussion on the FHE.org discord server: (inside the #concrete channel).
Do you have a question about Zama? You can write us on or send us an email at: [email protected]
Pandas
Concrete-ML provides partial support for Pandas, with most available models (linear and tree-based models) usable on Pandas dataframes the same way they would be used with NumPy arrays.
The table below summarizes the current compatibility:
Methods
Support Pandas dataframe
fit
✓
compile
✗
Example
The following example considers a LogisticRegression model on a simple classification problem. A more advanced example can be found in the , which considers a XGBClassifier.
concrete.ml.onnx.onnx_utils
module concrete.ml.onnx.onnx_utils
Utils to interpret an ONNX model with numpy.
Global Variables
ATTR_TYPES
ATTR_GETTERS
ONNX_OPS_TO_NUMPY_IMPL
function get_attribute
Get the attribute from an ONNX AttributeProto.
Args:
attribute (onnx.AttributeProto): The attribute to retrieve the value from.
Returns:
Any: The stored attribute value.
function get_op_name
Construct the qualified name of the ONNX operator.
Args:
node (Any): ONNX graph node
Returns:
result (str): qualified name
function execute_onnx_with_numpy
Execute the provided ONNX graph on the given inputs.
Args:
graph (onnx.GraphProto): The ONNX graph to execute.
*inputs: The inputs of the graph.
Returns:
Tuple[numpy.ndarray]: The result of the graph's execution.
Key Concepts
Concrete-ML is built on top of Concrete-Numpy, which enables Numpy programs to be converted into FHE circuits.
Lifecycle of a Concrete-ML model
Pruning
Pruning is a method to reduce neural network complexity, usually applied in order to reduce the computation cost or memory size. Pruning is used in Concrete-ML to control the size of accumulators in neural networks, thus making them FHE-compatible. See for an explanation of accumulator bit-width constraints.
Overview of pruning in Concrete-ML
Pruning is used in Concrete-ML for two types of neural networks:
Compilation
Compilation of a model produces machine code that executes the model on encrypted data. In some cases, notably in the client/server setting, the compilation can be done by the server when loading the model for serving.
As FHE execution is much slower than execution on non-encrypted data, Concrete-ML has a simulation mode, using an execution mode named the Virtual Library. Since, by default, the cryptographic parameters are chosen such that the results obtained in FHE are the same as those on clear data, the Virtual Library allows you to benchmark models quickly during development.
Compilation
Built-in Model Examples
The following table summarizes the various examples in this section, along with their accuracies.
Model
Data-set
Metric
Floating Point
Simulation
FHE
Importing ONNX
Internally, Concrete-ML uses operators as intermediate representation (or IR) for manipulating machine learning models produced through export for , and .
As ONNX is becoming the standard exchange format for neural networks, this allows Concrete-ML to be flexible while also making model representation manipulation quite easy. In addition, it allows for straight-forward mapping to NumPy operators, supported by Concrete-Numpy to use Concrete stack's FHE conversion capabilities.
Torch to NumPy conversion using ONNX
concrete.ml.torch.numpy_module
module concrete.ml.torch.numpy_module
A torch to numpy module.
Inference in the Cloud
Concrete-ML models can be easily deployed in a client/server setting, enabling the creation of privacy-preserving services in the cloud.
As seen in the , a Concrete-ML model, once compiled to FHE, generates machine code that performs the inference on private data. Furthermore, secret encryption keys are needed so that the user can securely encrypt their data and decrypt the inference result. An evaluation key is also needed for the server to securely process the user's encrypted data.
Keys are generated by the user once for each service they use, based on the model the service provides and its cryptographic parameters.
The overall communications protocol to enable cloud deployment of machine learning services can be summarized in the following diagram:
get_onnx_opset_version(onnx_model: ModelProto) → int
from concrete.ml.sklearn import XGBoostClassifier
clf = XGBoostClassifier()
clf.fit(X_train, y_train)
# Here comes the p_error parameter
clf.compile(X_train, p_error = 0.1)
The model developer deploys the compiled machine learning model to the server. This model includes the cryptographic parameters. The server is now ready to provide private inference.
The client requests the cryptographic parameters (also called "client specs"). Once it gets them from the server, the secret and evaluation keys are generated.
The client sends the evaluation key to the server. The server is now ready to accept requests from this client. The client sends their encrypted data.
The server uses the evaluation key to securely run inference on the user's data and sends back the encrypted result.
The client now decrypts the result and can send back new requests.
Concrete-ML implements machine model inference using Concrete-Numpy as a backend. In order to execute in FHE, a numerical program written in Concrete-Numpy needs to be compiled. This functionality is described here, and Concrete-ML hides away most of the complexity of this step. The entire compilation process is done by Concrete-Numpy.
From the perspective of the Concrete-ML user, the compilation process performed by Concrete-Numpy can be broken up into 3 steps:
Numpy program tracing and creation of a Concrete-Numpy op-graph
checking that the op-graph is FHE compatible
producing machine code for the op-graph. This step automatically determines cryptographic parameters
Additionally, the client/server API packages the result of the last step in a way that allows the deployment of the encrypted circuit to a server and key generation, encryption and decryption on the client side.
Simulation with the Virtual Library
The first step in the list above takes a Python function implemented using the Concrete-Numpy supported operation set and transforms it into an executable operation graph.
The result of this single step of the compilation pipeline allows the:
execution of the op-graph, which includes TLUs, on clear non-encrypted data. This is, of course, not secure, but it is much faster than executing in FHE. This mode is useful for debugging, i.e. to find the appropriate hyper-parameters. This mode is called the Virtual Library.
verification of the maximum bit-width of the op-graph, to determine FHE compatibility, without actually compiling the circuit to machine code.
Enabling Virtual Library execution requires the definition of a compilation Configuration. As simulation does not execute in FHE, this can be considered unsafe:
Next, the following code uses the simulation mode for built-in models:
And finally, for custom models, it is possible to enable simulation using the following syntax:
Obtaining the simulated predictions of the models using the Virtual Library has the same syntax as execution in FHE:
Moreover, the maximum accumulator bit-width is determined as follows:
A simple Concrete-Numpy example
While Concrete-ML hides away all the Concrete-Numpy code that performs model inference, it can be useful to understand how Concrete-Numpy code works. Here is an toy example for a simple linear regression model on integers. Note that this is just an example to illustrate compilation concepts. Generally, it is recommended to use the built-in models, which provide linear regression out of the box.
import numpy
from sklearn.datasets import make_classification
from sklearn.model_selection import train_test_split
from concrete.ml.sklearn import LogisticRegression
# Lets create a synthetic data-set
x, y = make_classification(n_samples=100,
class_sep=2, n_features=4, random_state=42)
X_train, X_test, y_train, y_test = train_test_split(
x, y, test_size=0.2, random_state=42
)
# Now we train in plaintext using quantization
model = LogisticRegression(n_bits=2)
model.fit(X_train, y_train)
y_pred_clear = model.predict(X_test)
# Finally we compile and run inference on encrypted inputs!
model.compile(x)
y_pred_fhe = model.predict(X_test, execute_in_fhe=True)
print("In clear :", y_pred_clear)
print("In FHE :", y_pred_fhe)
print("Comparison:", (y_pred_fhe == y_pred_clear))
# Output:
# In clear : [0 1 0 1 0 1 0 1 1 1 0 1 1 0 1 0 0 1 1 1]
# In FHE : [0 1 0 1 0 1 0 1 1 1 0 1 1 0 1 0 0 1 1 1]
# Comparison: [ True True True True True True True True True True True True
# True True True True True True True True]
import numpy as np
import pandas as pd
from concrete.ml.sklearn import LogisticRegression
from sklearn.datasets import make_classification
from sklearn.model_selection import train_test_split
# Create the data set as a Pandas dataframe
X, y = make_classification(
n_samples=100,
n_features=2,
n_redundant=0,
random_state=2,
)
X, y = pd.DataFrame(X), pd.DataFrame(y)
# Retrieve train and test sets
X_train, X_test, y_train, y_test = train_test_split(X, y, test_size=0.4, random_state=42)
# Instantiate the model
model = LogisticRegression(n_bits=2)
# Fit the model
model.fit(X_train, y_train)
# Evaluate the model on the test set in clear
y_pred_clear = model.predict(X_test)
# Compile the model
model.compile(X_train.to_numpy())
# Perform the inference in FHE
# Warning: this will take a while. It is recommended to run this with a very small batch of
# examples first (e.g. N_TEST_FHE = 1)
# Note that here the encryption and decryption is done behind the scenes.
N_TEST_FHE = 1
y_pred_fhe = model.predict(X_test.head(N_TEST_FHE), execute_in_fhe=True)
# Assert that FHE predictions are the same as the clear predictions
print(f"{(y_pred_fhe == y_pred_clear[:N_TEST_FHE]).sum()} "
f"examples over {N_TEST_FHE} have a FHE inference equal to the clear inference.")
# Output:
# 1 examples over 1 have a FHE inference equal to the clear inference
COMPIL_CONFIG_VL = Configuration(
dump_artifacts_on_unexpected_failures=False,
enable_unsafe_features=True, # This is for our tests in Virtual Library only
)
quantized_numpy_module = compile_torch_model(
torch_model, # our model
X_train, # a representative input-set to be used for both quantization and compilation
n_bits={"net_inputs": 5, "op_inputs": 3, "op_weights": 3, "net_outputs": 5},
import_qat=is_qat, # signal to the conversion function whether the network is QAT
use_virtual_lib=True,
configuration=COMPIL_CONFIG_VL,
)
import numpy
from concrete.numpy.compilation import compiler
# Let's assume Quantization has been applied and we are left with integers only.
# This is essentially the work of Concrete-ML
# Some parameters (weight and bias) for our model taking a single feature
w = [2]
b = 2
# The function that implements our model
@compiler({"x": "encrypted"})
def linear_model(x):
return w @ x + b
# A representative input-set is needed to compile the function
# (used for tracing)
n_bits_input = 2
inputset = numpy.arange(0, 2**n_bits_input).reshape(-1, 1)
circuit = linear_model.compile(inputset)
# Use the API to get the maximum bit-width in the circuit
max_bit_width = circuit.graph.maximum_integer_bit_width()
print("Max bit_width = ", max_bit_width)
# Max bit_width = 4
# Test our FHE inference
circuit.encrypt_run_decrypt(numpy.array([3]))
# 8
# Print the graph of the circuit
print(circuit)
# %0 = 2 # ClearScalar<uint2>
# %1 = [2] # ClearTensor<uint2, shape=(1,)>
# %2 = x # EncryptedTensor<uint2, shape=(1,)>
# %3 = matmul(%1, %2) # EncryptedScalar<uint3>
# %4 = add(%3, %0) # EncryptedScalar<uint4>
# return %4
ONNX_COMPARISON_OPS_TO_NUMPY_IMPL_FLOAT
ONNX_COMPARISON_OPS_TO_NUMPY_IMPL_BOOL
ONNX_OPS_TO_NUMPY_IMPL_BOOL
IMPLEMENTED_ONNX_OPS
I. Model Development
Training. A model is trained using plaintext, non-encrypted, training data.
Quantization. The model is converted into an integer equivalent using quantization. Concrete-ML performs this step either during training (Quantization-Aware Training) or after training (Post-Training Quantization), depending on model type. Quantization converts inputs, model weights and all intermediate values of the inference computation to integers. More information is available here.
Simulation using the Virtual Library. Testing FHE models on very large datasets can take a long time. Furthermore, not all models are compatible with FHE constraints out-of-the-box. Simulation using the Virtual Library allows you to execute a model that was quantized, to measure the accuracy it would have in FHE, but also to determine the modifications required to make it FHE compatible. Simulation is described in more details .
Compilation. Once the model is quantized, simulation can confirm it has good accuracy in FHE. The model then needs to be compiled using Concrete's FHE compiler to produce an equivalent FHE circuit. This circuit is represented as an MLIR program consisting of low level cryptographic operations. You can read more about FHE compilation , MLIR and about the low-level Concrete library .
Inference. The compiled model can then be executed on encrypted data, once the proper keys have been generated. The model can also be deployed to a server and used to run private inference on encrypted inputs.
You can see some examples of the model development workflow here.
II. Model deployment
Client/Server deployment. In a client/server setting, the model can be exported in a way that:
allows the client to generate keys, encrypt and decrypt.
provides a compiled model that can run on the server to perform inference on encrypted data
Key generation. The data owner (client) needs to generate a pair of private keys (to encrypt/decrypt their data and results) and a public evaluation key (for the model's FHE evaluation on the server).
You can see an example of the model deployment workflow here.
Cryptography concepts
Concrete-ML and Concrete-Numpy are tools that hide away the details of the underlying cryptography scheme, called TFHE. However, some cryptography concepts are still useful when using these two toolkits:
Encryption/Decryption. These operations transform plaintext, i.e. human-readable information, into ciphertext, i.e. data that contains a form of the original plaintext that is unreadable by a human or computer without the proper key to decrypt it. Encryption takes plaintext and an encryption key and produces ciphertext, while decryption is the inverse operation.
Encrypted inference. FHE allows a third party to execute (i.e. run inference or predict) a machine learning model on encrypted data (a ciphertext). The result of the inference is also encrypted and can only be read by the person who gets the decryption key.
Keys. A key is a series of bits used within an encryption algorithm for encrypting data so that the corresponding ciphertext appears random.
Key generation. Cryptographic keys need to be generated using random number generators. Their size may be large and key generation may take a long time. However, keys only need to be generated once for each model a client uses.
Guaranteed correctness of encrypted computations. To achieve security, TFHE, the underlying encryption scheme, adds random noise as ciphertexts. This can induce errors during processing of encrypted data, depending on noise parameters. By default, Concrete-ML uses parameters that ensure the correctness of the encrypted computation, so you do not need to take into account the noise parametrization. Therefore, results on encrypted data will be the same as the results of simulation on clear data.
Model accuracy considerations under FHE constraints
To respect FHE constraints, all numerical programs over encrypted data must have all inputs, constants and intermediate values represented with integers of a maximum of 8 bits.
Thus, Concrete-ML quantizes the input data and model outputs in the same way as weights and activations. The main levers to control accumulator bit-width are the numbers of bits used for the inputs, weights and activations of the model. These parameters are crucial to comply with the constraint on accumulator bit-widths. Please refer to the quantization documentation for more details about how to develop models with quantization in Concrete-ML.
However, these methods may cause a reduction in the accuracy of the model since its representative power is diminished. Most importantly, carefully choosing a quantization approach can alleviate accuracy loss, all the while allowing compilation to FHE. Concrete-ML offers built-in models that already include quantization algorithms, and users only need to configure some of their parameters, such as the number of bits, discussed above. See the advanced quantization guide for information about configuring these parameters for various models.
Additional specific methods can help to make models compatible with FHE constraints. For instance, dimensionality reduction can reduce the number of input features and, thus, the maximum accumulator bit-width reached within a circuit. Similarly, sparsity-inducing training methods, such as pruning, de-activate some features during inference, which also helps. For now, dimensionality reduction is considered as a pre-processing step, while pruning is used in the built-in neural networks.
Built-in neural networks include a pruning mechanism that can be parameterized by the user. The pruning type is based on L1-norm. To comply with FHE constraints, Concrete-ML uses unstructured pruning, as the aim is not to eliminate neurons or convolutional filters completely, but to decrease their accumulator bit-width.
Custom neural networks, to work well under FHE constraints, should include pruning. When implemented with PyTorch, you can use the framework's pruning mechanism (e.g.L1-Unstructured) to good effect.
Basics of pruning
In neural networks, a neuron computes a linear combination of inputs and learned weights, then applies an activation function.
Artificial Neuron (from: wikipedia)
The neuron computes:
yk=ϕ(∑iwixi)
When building a full neural network, each layer will contain multiple neurons, which are connected to the neuron outputs of a previous layer or to the inputs.
Fully Connected Neural Network
For every neuron shown in each layer of the figure above, the linear combinations of inputs and learned weights are computed. Depending on the values of the inputs and weights, the sum vk=∑iwixi - which for Concrete-ML neural networks is computed with integers - can take a range of different values.
To respect the bit-width constraint of the FHE Table Lookup, the values of the accumulator vk must remain small to be representable with only 8 bits. In other words, the values must be between 0 and 255.
Pruning a neural network entails fixing some of the weights wk to be zero during training. This is advantageous to meet FHE constraints, as irrespective of the distribution of xi, multiplying these input values by 0 does not increase the accumulator value.
Fixing some of the weights to 0 makes the network graph look more similar to the following:
Pruned Fully Connected Neural Network
While pruning weights can reduce the prediction performance of the neural network, studies show that a high level of pruning (above 50%) can often be applied. See here how Concrete-ML uses pruning in Fully Connected Neural Networks.
Pruning in practice
In the formula above, in the worst-case, the maximum number of the input and weights that can make the result exceed $n$ bits is given by:
Ω=floor((2nweights−1)(2ninputs−1)2nmax−1)
Here, nmax=8 is the maximum precision allowed.
For example, if nweights=2 and ninputs=2 with nmax=8, the worst case is where all inputs and weights are equal to their maximal value 22−1=3. In this case, there can be at most Ω=28 elements in the multi-sums.
In practice, the distribution of the weights of a neural network is Gaussian, with many weights either 0 or having a small value. This enables exceeding the worst-case number of active neurons without having to risk overflowing the bit-width. In built-in neural networks, the parameter n_hidden_neurons_multiplier is multiplied with Ω to determine the total number of non-zero weights that should be kept in a neuron.
The diagram below gives an overview of the steps involved in the conversion of an ONNX graph to a FHE compatible format, i.e. a format that can be compiled to FHE through Concrete-Numpy.
All Concrete-ML built-in models follow the same pattern for FHE conversion:
The models are trained with sklearn or PyTorch
All models have a PyTorch implementation for inference. This implementation is provided either by a third-party tool such as Hummingbird or implemented directly in Concrete-ML.
The PyTorch model is exported to ONNX. For more information on the use of ONNX in Concrete-ML, see here.
The Concrete-ML ONNX parser checks that all the operations in the ONNX graph are supported and assigns reference NumPy operations to them. This step produces a NumpyModule.
Quantization is performed on the , producing a . Two steps are performed: calibration and assignment of equivalent objects to each ONNX operation. The QuantizedModule class is the quantized counterpart of the NumpyModule.
Once the QuantizedModule is built, Concrete-Numpy is used to trace the ._forward() function of the QuantizedModule.
Moreover, by passing a user provided nn.Module to step 2 of the above process, Concrete-ML supports custom user models. See the associated FHE-friendly model documentation for instructions about working with such models.
Torch compilation flow with ONNX
Once an ONNX model is imported, it is converted to a NumpyModule, then to a QuantizedModule and, finally, to a FHE circuit. However, as the diagram shows, it is perfectly possible to stop at the NumpyModule level if you just want to run the PyTorch model as NumPy code without doing quantization.
In order to better understand how Concrete-ML works under the hood, it is possible to access each model in their ONNX format and then either print it or visualize it by importing the associated file in Netron. For example, with LogisticRegression:
General interface to transform a torch.nn.Module to numpy module.
Args:
torch_model (Union[nn.Module, onnx.ModelProto]): A fully trained, torch model along with its parameters or the onnx graph of the model.
dummy_input (Union[torch.Tensor, Tuple[torch.Tensor, ...]]): Sample tensors for all the module inputs, used in the ONNX export to get a simple to manipulate nn representation.
debug_onnx_output_file_path: (Optional[Union[Path, str]], optional): An optional path to indicate where to save the ONNX file exported by torch for debug. Defaults to None.
method __init__
property onnx_model
Get the ONNX model.
.. # noqa: DAR201
Returns:
_onnx_model (onnx.ModelProto): the ONNX model
method forward
Apply a forward pass on args with the equivalent numpy function only.
Args:
*args: the inputs of the forward function
Returns:
Union[numpy.ndarray, Tuple[numpy.ndarray, ...]]: result of the forward on the given inputs
Quantization
Quantization is the process of constraining an input from a continuous or otherwise large set of values (such as real numbers) to a discrete set (such as integers).
This means that some accuracy in the representation is lost (e.g. a simple approach is to eliminate least-significant bits). However, in many cases in machine learning, it is possible to adapt the models to give meaningful results while using these smaller data types. This significantly reduces the number of bits necessary for intermediary results during the execution of these machine learning models.
Since FHE is currently limited to 8-bit integers, it is necessary to quantize models to make them compatible. As a general rule, the smaller the precision models, the better the FHE performance.
Overview of quantization in Concrete-ML
Quantization implemented in Concrete-ML is applied in two ways:
Built-in models apply quantization internally and the user only needs to configure some quantization parameters. This approach requires little work by the user but may not be a one-size-fits-all solution for all types of models. The final quantized model is FHE friendly and ready to predict over encrypted data. In this setting, Post-Training Quantization (PTQ) is for linear models, data quantization is used for tree-based models and, finally, Quantization Aware Training (QAT) is included in the built-in neural network models.
For custom neural networks with more complex topology, obtaining FHE-compatible models with good accuracy requires QAT. Concrete-ML offers the possibility for the user to perform quantization before compiling to FHE. This can be achieved through a third-party library that offers QAT tools, such as for PyTorch. In this approach, the user is responsible for implementing a full-integer model, respecting FHE constraints. Please refer to the for tips on designing FHE neural networks.
While Concrete-ML quantizes machine learning models, the data the client has is often in floating point. The Concrete-ML models provide APIs to quantize inputs and de-quantize outputs.
Please note that the floating point input is quantized in the clear, i.e. it is converted to integers before being encrypted. Moreover, the model's output are also integers and are decrypted before de-quantization.
Basics of quantization
Let be the range of a value to quantize where is the minimum and is the maximum. To quantize a range of floating point values (in ) to integer values (in ), the first step is to choose the data type that is going to be used. Concrete, the framework used by Concrete-ML, is currently limited to 8-bit integers, so this will be the value used in this example. Knowing the number of bits that can be used for a value in the range , the scale can be computed :
where is the number of bits (). For the sake of example, let's take .
In practice, the quantization scale is then . This means the gap between consecutive representable values cannot be smaller than , which, in turn, means there can be a substantial loss of precision. Every interval of length will be represented by a value within the range .
The other important parameter from this quantization schema is the zero point value. This essentially brings the 0 floating point value to a specific integer. If the quantization scheme is asymmetric (quantized values are not centered in 0), the resulting integer will be in .
When using quantized values in a matrix multiplication or convolution, the equations for computing the result become more complex. The IntelLabs distiller quantization documentation provides a more of the maths used to quantize values and how to keep computations consistent.
Configuring model quantization parameters
Built-in models provide a simple interface for configuring quantization parameters, most notably the number of bits used for inputs, model weights, intermediary and output values.
For , the quantization is done post-training. Thus, the model is trained in floating point, and then, the best integer weight representations are found, depending on the distribution of inputs and weights. For these models, the user can select the value of the n_bits parameter.
For linear models, n_bits is used to quantize both model inputs and weights. Depending on the number of features, you can use a single integer value for the n_bits parameter, e.g. a value between 2 and 7. When the number of features is high, the n_bits parameter should be decreased if you encounter compilation errors. It is also possible to quantize inputs and weights with different number of bits by passing a dictionary to n_bits , containing the op_inputs and op_weights keys.
For , the training and test data is quantized. The maximum accumulator bit-width for a model trained with n_bits=n for this type of model is known beforehand: it will need n+1 bits. Thus, as Concrete-ML only supports up to 8-bit integers, n should be less than 8. Through experimentation, it was determined that in many cases a value of 5 or 6 bits gives the same accuracy as training in floating point.
Tree-based models can directly control the accumulator bit-width used. However, if 6 or 7 bits are not sufficient to obtain good accuracy on your data-set, one option is to use an ensemble model (RandomForest or XGBoost) and increase the number of trees in the ensemble. This, however, will have a detrimental impact on FHE execution speed.
For the built-in , several linear layers are used. Thus, the outputs of a layer are used as inputs to a new layer. Built-in neural networks use Quantization Aware Training. The parameters controlling the maximum accumulator bit-width are the number of weights and activation bits ( module__n_w_bits, module__n_a_bits ), but also the pruning factor. This factor is determined automatically by specifying a desired accumulator bit-width module__n_accum_bits and, optionally, a multiplier factor, module__n_hidden_neurons_multiplier.
Note that for the built-in linear models and neural networks, the maximum accumulator bit-width can not be precisely controlled. To use many input features and a high number of bits is beneficial for model accuracy, but it can conflict with the 8-bit accumulator constraint. Finding the best quantization parameters to maximize accuracy can only be done through experimentation.
Quantizing model inputs and outputs
The models implemented in Concrete-ML provide features to let the user quantize the input data and de-quantize the output data.
In a client/server setting, the client is responsible for quantizing inputs before sending them, encrypted, to the server. Further, the client must de-quantize the encrypted integer results received from the server. See the section for more details.
Here is a simple example showing how to perform inference, starting from float values and ending up with float values. Note that the FHE engine that is compiled for the ML models does not support data batching.
Resources
IntelLabs distiller explanation of quantization:
concrete.ml.onnx.onnx_model_manipulations
module concrete.ml.onnx.onnx_model_manipulations
Some code to manipulate models.
function simplify_onnx_model
Simplify an ONNX model, removes unused Constant nodes and Identity nodes.
Args:
onnx_model (onnx.ModelProto): the model to simplify.
function remove_unused_constant_nodes
Remove unused Constant nodes in the provided onnx model.
Args:
onnx_model (onnx.ModelProto): the model for which we want to remove unused Constant nodes.
function remove_identity_nodes
Remove identity nodes from a model.
Args:
onnx_model (onnx.ModelProto): the model for which we want to remove Identity nodes.
function keep_following_outputs_discard_others
Keep the outputs given in outputs_to_keep and remove the others from the model.
Args:
onnx_model (onnx.ModelProto): the ONNX model to modify.
outputs_to_keep (Iterable[str]): the outputs to keep by name.
function remove_node_types
Remove unnecessary nodes from the ONNX graph.
Args:
onnx_model (onnx.ModelProto): The ONNX model to modify.
op_types_to_remove (List[str]): The node types to remove from the graph.
Raises:
ValueError: Wrong replacement by an Identity node.
function clean_graph_after_node_name
Clean the graph of the onnx model by removing nodes after the given node name.
Args:
onnx_model (onnx.ModelProto): The onnx model.
node_name (str): The node's name whose following nodes will be removed.
Raises:
ValueError: if the node name is not found and if fail_if_not_found is set
function clean_graph_after_node_op_type
Clean the graph of the onnx model by removing nodes after the given node type.
Args:
onnx_model (onnx.ModelProto): The onnx model.
node_op_type (str): The node's op_type whose following nodes will be removed.
Raises:
ValueError: if the node op_type is not found and if fail_if_not_found is set
concrete.ml.sklearn.tree
module concrete.ml.sklearn.tree
Implement the sklearn tree models.
class DecisionTreeClassifier
Implements the sklearn DecisionTreeClassifier.
method __init__
Initialize the DecisionTreeClassifier.
noqa: DAR101
property onnx_model
Get the ONNX model.
.. # noqa: DAR201
Returns:
onnx.ModelProto: the ONNX model
class DecisionTreeRegressor
Implements the sklearn DecisionTreeClassifier.
method __init__
Initialize the DecisionTreeRegressor.
noqa: DAR101
property onnx_model
Get the ONNX model.
.. # noqa: DAR201
Returns:
onnx.ModelProto: the ONNX model
concrete.ml.common.check_inputs
module concrete.ml.common.check_inputs
Check and conversion tools.
Utils that are used to check (including convert) some data types which are compatible with scikit-learn to numpy types.
function check_array_and_assert
sklearn.utils.check_array with an assert.
Equivalent of sklearn.utils.check_array, with a final assert that the type is one which is supported by Concrete-ML.
Args:
X (object): Input object to check / convert
Returns: The converted and validated array
function check_X_y_and_assert
sklearn.utils.check_X_y with an assert.
Equivalent of sklearn.utils.check_X_y, with a final assert that the type is one which is supported by Concrete-ML.
import onnx
from sklearn.datasets import make_classification
from sklearn.model_selection import train_test_split
from concrete.ml.sklearn import LogisticRegression
# Create the data for classification
x, y = make_classification(n_samples=100, class_sep=2, n_features=4, random_state=42)
# Retrieve train and test sets
X_train, X_test, y_train, y_test = train_test_split(
x, y, test_size=10, random_state=42
)
# Fix the number of bits to used for quantization
model = LogisticRegression(n_bits=2)
# Fit the model
model.fit(X_train, y_train)
# Access to the model
onnx_model = model.onnx_model
# Print the model
print(onnx.helper.printable_graph(onnx_model.graph))
# Save the model
onnx.save(onnx_model, "tmp.onnx")
# And then visualize it with Netron
# Assume quantized_module : QuantizedModule
# data: numpy.ndarray of float
# Quantization is done in the clear
x_test_q = quantized_module.quantize_input(data)
for i in range(x_test_q.shape[0]):
# Inputs must have size (1 x N) or (1 x C x H x W), we add the batch dimension with N=1
x_q = np.expand_dims(x_test_q[i, :], 0)
# Execute the model in FHE
out_fhe = quantized_module.forward_fhe.encrypt_run_decrypt(x_q)
# Dequantization is done in the clear
output = quantized_module.dequantize_output(out_fhe)
# For classifiers with multi-class outputs, the arg max is done in the clear
y_pred = np.argmax(output, 1)
fail_if_not_found
(bool): If true, abort if the node name is not found
fail_if_not_found
(bool): If true, abort if the node op_type is not found
*args
: The arguments to pass to check_X_y
**kwargs: The keyword arguments to pass to check_X_y
Global Variables
IMPLEMENTED_ONNX_OPS
OPSET_VERSION_FOR_ONNX_EXPORT
function get_equivalent_numpy_forward_and_onnx_model
Get the numpy equivalent forward of the provided torch Module.
Args:
torch_module (torch.nn.Module): the torch Module for which to get the equivalent numpy forward.
dummy_input (Union[torch.Tensor, Tuple[torch.Tensor, ...]]): dummy inputs for ONNX export.
output_onnx_file (Optional[Union[Path, str]]): Path to save the ONNX file to. Will use a temp file if not provided. Defaults to None.
Returns:
Tuple[Callable[..., Tuple[numpy.ndarray, ...]], onnx.GraphProto]: The function that will execute the equivalent numpy code to the passed torch_module and the generated ONNX model.
function get_equivalent_numpy_forward
Get the numpy equivalent forward of the provided ONNX model.
Args:
onnx_model (onnx.ModelProto): the ONNX model for which to get the equivalent numpy forward.
check_model (bool): set to True to run the onnx checker on the model. Defaults to True.
Raises:
ValueError: Raised if there is an unsupported ONNX operator required to convert the torch model to numpy.
Returns:
Callable[..., Tuple[numpy.ndarray, ...]]: The function that will execute the equivalent numpy function.
concrete.ml.torch.compile
module concrete.ml.torch.compile
torch compilation function.
Global Variables
MAXIMUM_TLU_BIT_WIDTH
DEFAULT_P_ERROR_PBS
OPSET_VERSION_FOR_ONNX_EXPORT
function convert_torch_tensor_or_numpy_array_to_numpy_array
Convert a torch tensor or a numpy array to a numpy array.
Args:
torch_tensor_or_numpy_array (Tensor): the value that is either a torch tensor or a numpy array.
Returns:
numpy.ndarray: the value converted to a numpy array.
function compile_torch_model
Compile a torch module into an FHE equivalent.
Take a model in torch, turn it to numpy, quantize its inputs / weights / outputs and finally compile it with Concrete-Numpy
Args:
torch_model (torch.nn.Module): the model to quantize
torch_inputset (Dataset): the inputset, can contain either torch tensors or numpy.ndarray, only datasets with a single input are supported for now.
Returns:
QuantizedModule: The resulting compiled QuantizedModule.
function compile_onnx_model
Compile a torch module into an FHE equivalent.
Take a model in torch, turn it to numpy, quantize its inputs / weights / outputs and finally compile it with Concrete-Numpy
Args:
onnx_model (onnx.ModelProto): the model to quantize
torch_inputset (Dataset): the inputset, can contain either torch tensors or numpy.ndarray, only datasets with a single input are supported for now.
Returns:
QuantizedModule: The resulting compiled QuantizedModule.
function compile_brevitas_qat_model
Compile a Brevitas Quantization Aware Training model.
The torch_model parameter is a subclass of torch.nn.Module that uses quantized operations from brevitas.qnn. The model is trained before calling this function. This function compiles the trained model to FHE.
Args:
torch_model (torch.nn.Module): the model to quantize
torch_inputset (Dataset): the inputset, can contain either torch tensors or numpy.ndarray, only datasets with a single input are supported for now.
Returns:
QuantizedModule: The resulting compiled QuantizedModule.
External Libraries
Hummingbird
Hummingbird is a third-party, open-source library that converts machine learning models into tensor computations, and it can export these models to ONNX. The list of supported models can be found in the Hummingbird documentation.
Concrete-ML allows the conversion of an ONNX inference to NumPy inference (note that NumPy is always the entry point to run models in FHE with Concrete ML).
Hummingbird exposes a convert function that can be imported as follows from the hummingbird.ml package:
This function can be used to convert a machine learning model to an ONNX as follows:
In theory, the resulting onnx_model could be used directly within Concrete-ML's get_equivalent_numpy_forward method (as long as all operators present in the ONNX model are implemented in NumPy) and get the NumPy inference.
In practice, there are some steps needed to clean the ONNX output and make the graph compatible with Concrete-ML, such as applying quantization where needed or deleting/replacing non-FHE friendly ONNX operators (such as Softmax and ArgMax).
Skorch
Concrete-ML uses to implement multi-layer, fully-connected PyTorch neural networks in a way that is compatible with the Scikit-learn API.
This wrapper implements Torch training boilerplate code, alleviating the work that needs to be done by the user. It is possible to add hooks during the training phase, for example once an epoch is finished.
Skorch allows the user to easily create a classifier or regressor around a neural network (NN), implemented in Torch as a nn.Module, which is used by Concrete-ML to provide a fully-connected multi-layer NN with a configurable number of layers and optional pruning (see and the for more information).
Under the hood, Concrete-ML uses a Skorch wrapper around a single PyTorch module, SparseQuantNeuralNetImpl. More information can be found .
Brevitas
is a quantization aware learning toolkit built on top of PyTorch. It provides quantization layers that are one-to-one equivalents to PyTorch layers, but also contain operations that perform the quantization during training.
While Brevitas provides many types of quantization, for Concrete-ML, a custom "mixed integer" quantization applies. This "mixed integer" quantization is much simpler than the "integer only" mode of Brevitas. The "mixed integer" network design is defined as:
all weights and activations of convolutional, linear and pooling layers must be quantized (e.g. using Brevitas layers, QuantConv2D, QuantAvgPool2D, QuantLinear)
PyTorch floating point versions of univariate functions can be used. E.g. torch.relu, nn.BatchNormalization2D, torch.max
The "mixed integer" mode used in Concrete-ML neural networks is based on the that makes both weights and activations representable as integers during training. However, through the use of lookup tables in Concrete-ML, floating point univariate PyTorch functions are supported.
For "mixed integer" quantization to work, the first layer of a Brevitas nn.Module must be a QuantIdentity layer. However, you can then use functions such as torch.sigmoid on the result of such a quantizing operation.
For examples of such a "mixed integer" network design, please see the Quantization Aware Training examples:
or go to the .
You can also refer to the class which is the basis of the built-in NeuralNetworkClassifier.
concrete.ml.sklearn.svm
module concrete.ml.sklearn.svm
Implement Support Vector Machine.
class LinearSVR
A Regression Support Vector Machine (SVM).
method __init__
property fhe_circuit
Get the FHE circuit.
Returns:
Circuit: the FHE circuit
property input_quantizers
Get the input quantizers.
Returns:
List[QuantizedArray]: the input quantizers
property onnx_model
Get the ONNX model.
.. # noqa: DAR201
Returns:
onnx.ModelProto: the ONNX model
property output_quantizers
Get the input quantizers.
Returns:
List[QuantizedArray]: the input quantizers
property quantize_input
Get the input quantization function.
Returns:
Callable : function that quantizes the input
class LinearSVC
A Classification Support Vector Machine (SVM).
method __init__
property fhe_circuit
Get the FHE circuit.
Returns:
Circuit: the FHE circuit
property input_quantizers
Get the input quantizers.
Returns:
List[QuantizedArray]: the input quantizers
property onnx_model
Get the ONNX model.
.. # noqa: DAR201
Returns:
onnx.ModelProto: the ONNX model
property output_quantizers
Get the input quantizers.
Returns:
List[QuantizedArray]: the input quantizers
property quantize_input
Get the input quantization function.
Returns:
Callable : function that quantizes the input
Quantization tools
Quantizing data
Concrete-ML has support for quantized ML models and also provides quantization tools for Quantization Aware Training and Post-Training Quantization. The core of this functionality is the conversion of floating point values to integers and back. This is done using QuantizedArray in concrete.ml.quantization.
The QuantizedArray class takes several arguments that determine how float values are quantized:
n_bits that defines the precision of the quantization
values are floating point values that will be converted to integers
is_signed
See also the reference for more information:
It is also possible to use symmetric quantization, where the integer values are centered around 0:
In the following example, showing the de-quantization of model outputs, the QuantizedArray class is used in a different way. Here it uses pre-quantized integer values and has the scale and zero-point set explicitly. Once the QuantizedArray is constructed, calling dequant() will compute the floating point values corresponding to the integer values qvalues, which are the output of the forward_fhe.encrypt_run_decrypt(..) call.
Quantized modules
Machine learning models are implemented with a diverse set of operations, such as convolution, linear transformations, activation functions and element-wise operations. When working with quantized values, these operations cannot be carried out in an equivalent way as for floating point values. With quantization, it is necessary to re-scale the input and output values of each operation to fit in the quantization domain.
In Concrete-ML, the quantized equivalent of a scikit-learn model or a PyTorch nn.Module is the QuantizedModule. Note that only inference is implemented in the QuantizedModule, and it is built through a conversion of the inference function of the corresponding scikit-learn or PyTorch module.
Built-in neural networks expose the quantized_module member, while a QuantizedModule is also the result of the compilation of custom models through compile_torch_model and compile_brevitas_qat_model.
The quantized versions of floating point model operations are stored in the QuantizedModule. The ONNX_OPS_TO_QUANTIZED_IMPL dictionary maps ONNX floating point operators (e.g. Gemm) to their quantized equivalent (e.g. QuantizedGemm). For more information on implementing these operations, please see the .
The computation graph is taken from the corresponding floating point ONNX graph exported from scikit-learn , or from the ONNX graph exported by PyTorch. Calibration is used to obtain quantized parameters for the operations in the QuantizedModule. Parameters are also determined for the quantization of inputs during model deployment.
Calibration is the process of determining the typical distributions of values encountered for the intermediate values of a model during inference.
To perform calibration, an interpreter goes through the ONNX graph in and stores the intermediate results as it goes. The statistics of these values determine quantization parameters.
That QuantizedModule generates the Concrete-Numpy function that is compiled to FHE. The compilation will succeed if the intermediate values conform to the 8-bits precision limit of the Concrete stack. See for details.
Resources
Lei Mao's blog on quantization:
Google paper on neural network quantization and integer-only inference:
Debugging Models
This section provides a set of tools and guidelines to help users build optimized FHE-compatible models.
Virtual library
The Virtual Lib in Concrete-ML is a prototype that provides drop-in replacements for Concrete-Numpy's compiler, allowing users to simulate what would happen when converting a model to FHE without the current bit-width constraint. Additionally, it quickly simulates the behavior with 8 bits or less without actually doing the FHE computations.
The Virtual Lib can be useful when developing and iterating on an ML model implementation. For example, you can check that your model is compatible in terms of operands (all integers) with the Virtual Lib compilation. Then, you can check how many bits your ML model would require, which can give you hints as to how it should be modified if you want to compile it to an actual FHE Circuit (not a simulated one) that only supports 8 bits of integer precision.
concrete.ml.quantization.quantized_module
module concrete.ml.quantization.quantized_module
QuantizedModule API.
Set Up the Project
Concrete-ML is a Python library, so Python should be installed to develop Concrete-ML. v3.8 and v3.9 are the only supported versions. Concrete-ML also uses Poetry and Make.
First of all, you need to git clone the project:
concrete.ml.sklearn.xgb
module concrete.ml.sklearn.xgb
Implements XGBoost models.
Neural Networks
Concrete-ML provides simple neural networks models with a Scikit-learn interface through the NeuralNetClassifier and NeuralNetRegressor classes.
Concrete-ML
The neural network models are built with , which provides a scikit-learn like interface to Torch models (more ).
The Virtual Lib, being pure Python and not requiring crypto key generation, can be much faster than the actual compilation and FHE execution, thus allowing for faster iterations, debugging and FHE simulation, regardless of the bit-width used. For example, this was used for the red/blue contours in the Classifier Comparison notebook, as computing in FHE for the whole grid and all the classifiers would take significant time.
The following example shows how to use the Virtual Lib in Concrete-ML. Simply add use_virtual_lib = True and enable_unsafe_features = True in a Configuration. The result of the compilation will then be a simulated circuit that allows for more precision or simulated FHE execution.
Compilation debugging
The following example produces a neural network that is not FHE-compatible:
Upon execution, the compiler will raise the following error:
Knowing that a linear/dense layer is implemented as a matrix multiplication, it can determine which parts of the op-graph listing in the exception message above correspond to which layers.
Layer weights initialization:
Input processing and quantization:
First dense layer and activation function:
Second dense layer and activation function:
Third dense layer and output quantization:
We can see here that the error is in the second layer. Reducing the number of neurons in this layer will resolve the error and make the network FHE-compatible:
Complexity analysis
In FHE, univariate functions are encoded as table lookups, which are then implemented using Programmable Bootstrapping (PBS). PBS is a powerful technique but will require significantly more computing resources, and thus time, than simpler encrypted operations such matrix multiplications, convolution or additions.
Furthermore, the cost of PBS will depend on the bit-width of the compiled circuit. Every additional bit in the maximum bit-width raises the complexity of the PBS by a significant factor. It may be of interest to the model developer, then, to determine the bit-width of the circuit and the amount of PBS it performs.
This can be done by inspecting the MLIR code produced by the compiler:
Concrete-ML Model
Compiled MLIR model
There are several calls to FHELinalg.apply_mapped_lookup_table and FHELinalg.apply_lookup_table. These calls apply PBS to the cells of their input tensors. Their inputs in the listing above are: tensor<1x2x!FHE.eint<8>> for the first and last call and tensor<1x50x!FHE.eint<8>> for the two calls in the middle. Thus, PBS is applied 104 times.
Getting the bit-width of the circuit is then simply:
Decreasing the number of bits and the number of PBS induces large reductions in the computation time of the compiled circuit.
# Disable Hummingbird warnings for pytest.
import warnings
warnings.filterwarnings("ignore")
from hummingbird.ml import convert
from sklearn.datasets import make_classification
from sklearn.linear_model import LogisticRegression
# Instantiate the logistic regression from sklearn
lr = LogisticRegression()
# Create synthetic data
X, y = make_classification(
n_samples=100, n_features=20, n_classes=2
)
# Fit the model
lr.fit(X, y)
# Convert the model to ONNX
onnx_model = convert(lr, backend="onnx", test_input=X).model
class SparseQuantNeuralNetImpl(nn.Module):
"""Sparse Quantized Neural Network classifier.
import torch.nn as nn
class QATnetwork(nn.Module):
def __init__(self):
super(QATnetwork, self).__init__()
self.quant_inp = qnn.QuantIdentity(
bit_width=4, return_quant_tensor=True)
# ...
def forward(self, x):
out = self.quant_inp(x)
return torch.sigmoid(out)
# ...
from concrete.ml.quantization import QuantizedArray
import numpy
numpy.random.seed(0)
A = numpy.random.uniform(-2, 2, 10)
print("A = ", A)
# array([ 0.19525402, 0.86075747, 0.4110535, 0.17953273, -0.3053808,
# 0.58357645, -0.24965115, 1.567092 , 1.85465104, -0.46623392])
q_A = QuantizedArray(7, A)
print("q_A.qvalues = ", q_A.qvalues)
# array([ 37, 73, 48, 36, 9,
# 58, 12, 112, 127, 0])
# the quantized integers values from A.
print("q_A.quantizer.scale = ", q_A.quantizer.scale)
# 0.018274684777173276, the scale S.
print("q_A.quantizer.zero_point = ", q_A.quantizer.zero_point)
# 26, the zero point Z.
print("q_A.dequant() = ", q_A.dequant())
# array([ 0.20102153, 0.85891018, 0.40204307, 0.18274685, -0.31066964,
# 0.58478991, -0.25584559, 1.57162289, 1.84574316, -0.4751418 ])
# Dequantized values.
import_qat (bool): Set to True to import a network that contains quantizers and was trained using quantization aware training
configuration (Configuration): Configuration object to use during compilation
compilation_artifacts (DebugArtifacts): Artifacts object to fill during compilation
show_mlir (bool): if set, the MLIR produced by the converter and which is going to be sent to the compiler backend is shown on the screen, e.g., for debugging or demo
n_bits: the number of bits for the quantization
use_virtual_lib (bool): set to use the so called virtual lib simulating FHE computation. Defaults to False
p_error (Optional[float]): probability of error of a PBS
import_qat (bool): Flag to signal that the network being imported contains quantizers in in its computation graph and that Concrete ML should not requantize it.
configuration (Configuration): Configuration object to use during compilation
compilation_artifacts (DebugArtifacts): Artifacts object to fill during compilation
show_mlir (bool): if set, the MLIR produced by the converter and which is going to be sent to the compiler backend is shown on the screen, e.g., for debugging or demo
n_bits: the number of bits for the quantization
use_virtual_lib (bool): set to use the so called virtual lib simulating FHE computation. Defaults to False.
p_error (Optional[float]): probability of error of a PBS
n_bits (Union[int,dict]): the number of bits for the quantization
configuration (Configuration): Configuration object to use during compilation
compilation_artifacts (DebugArtifacts): Artifacts object to fill during compilation
show_mlir (bool): if set, the MLIR produced by the converter and which is going to be sent to the compiler backend is shown on the screen, e.g., for debugging or demo
use_virtual_lib (bool): set to use the so called virtual lib simulating FHE computation, defaults to False.
p_error (Optional[float]): probability of error of a PBS
output_onnx_file (str): temporary file to store ONNX model. If None a temporary file is generated
Global Variables
DEFAULT_P_ERROR_PBS
class QuantizedModule
Inference for a quantized model.
method __init__
property fhe_circuit
Get the FHE circuit.
Returns:
Circuit: the FHE circuit
property is_compiled
Return the compiled status of the module.
Returns:
bool: the compiled status of the module.
property onnx_model
Get the ONNX model.
.. # noqa: DAR201
Returns:
_onnx_model (onnx.ModelProto): the ONNX model
property post_processing_params
Get the post-processing parameters.
Returns:
Dict[str, Any]: the post-processing parameters
method compile
Compile the forward function of the module.
Args:
q_inputs (Union[Tuple[numpy.ndarray, ...], numpy.ndarray]): Needed for tracing and building the boundaries.
configuration (Optional[Configuration]): Configuration object to use during compilation
compilation_artifacts (Optional[DebugArtifacts]): Artifacts object to fill during
show_mlir (bool): if set, the MLIR produced by the converter and which is going to be sent to the compiler backend is shown on the screen, e.g., for debugging or demo. Defaults to False.
use_virtual_lib (bool): set to use the so called virtual lib simulating FHE computation. Defaults to False.
p_error (Optional[float]): probability of error of a PBS.
Returns:
Circuit: the compiled Circuit.
method dequantize_output
Take the last layer q_out and use its dequant function.
Args:
qvalues (numpy.ndarray): Quantized values of the last layer.
Returns:
numpy.ndarray: Dequantized values of the last layer.
method forward
Forward pass with numpy function only.
Args:
*qvalues (numpy.ndarray): numpy.array containing the quantized values.
Returns:
(numpy.ndarray): Predictions of the quantized model
method forward_and_dequant
Forward pass with numpy function only plus dequantization.
Args:
*q_x (numpy.ndarray): numpy.ndarray containing the quantized input values. Requires the input dtype to be uint8.
Returns:
(numpy.ndarray): Predictions of the quantized model
method post_processing
Post-processing of the quantized output.
Args:
qvalues (numpy.ndarray): numpy.ndarray containing the quantized input values.
Returns:
(numpy.ndarray): Predictions of the quantized model
method quantize_input
Take the inputs in fp32 and quantize it using the learned quantization parameters.
Set the quantization parameters for the module's inputs.
Args:
*input_q_params (UniformQuantizer): The quantizer(s) for the module.
Some tests require files tracked by git-lfs to be downloaded. To do so, please follow the instructions on
, then run git lfs pull.
Automatic installation
A simple way to have everything installed is to use the development Docker (see the Docker setup guide). On Linux and macOS, you have to run the script in ./script/make_utils/setup_os_deps.sh. Specify the --linux-install-python flag if you want to install python3.8 as well on apt-enabled Linux distributions. The script should install everything you need for Docker and bare OS development (you can first review the content of the file to check what it will do).
For Windows users, the setup_os_deps.sh script does not install dependencies because of how many different installation methods there are/lack of a single package manager.
The first step is to install Python (as some of the dev tools depend on it), then Poetry. In addition to installing Python, you are still going to need the following software available on path on Windows, as some of the basic dev tools depend on them:
git
jq
make
Development on Windows only works with the Docker environment. Follow .
Manual installation
Python
To manually install Python, you can follow this guide (alternatively, you can google how to install Python 3.8 (or 3.9)).
Poetry
Poetry is used as the package manager. It drastically simplifies dependency and environment management. You can follow this official guide to install it.
As there is no concrete-compiler package for Windows, only the dev dependencies can be installed. This requires Poetry >= 1.2.
Make
The dev tools use make to launch the various commands.
On Linux, you can install make from your distribution's preferred package manager.
On macOS, you can install a more recent version of make via brew:
It is possible to install gmake as make. Check this StackOverflow post for more info.
In the following sections, be sure to use the proper make tool for your system: make, gmake, or other.
Cloning the repository
To get the source code of Concrete-ML, clone the code repository using the link for your favourite communication protocol (ssh or https).
Setting up environment on your host OS
We are going to make use of virtual environments. This helps to keep the project isolated from other Python projects in the system. The following commands will create a new virtual environment under the project directory and install dependencies to it.
The following command will not work on Windows if you don't have Poetry >= 1.2.
Activating the environment
Finally, activate the newly created environment using the following command:
macOS or Linux
Windows
Setting up environment on Docker
Docker automatically creates and sources a venv in ~/dev_venv/
The venv persists thanks to volumes. It also creates a volume for ~/.cache to speed up later reinstallations. You can check which Docker volumes exist with:
You can still run all make commands inside Docker (to update the venv, for example). Be mindful of the current venv being used (the name in parentheses at the beginning of your command prompt).
Leaving the environment
After your work is done, you can simply run the following command to leave the environment:
Syncing environment with the latest changes
From time to time, new dependencies will be added to the project or the old ones will be removed. The command below will make sure the project has the proper environment, so run it regularly!
Troubleshooting your environment
in your OS
If you are having issues, consider using the dev Docker exclusively (unless you are working on OS-specific bug fixes or features).
Here are the steps you can take on your OS to try and fix issues:
At this point, you should consider using Docker as nobody will have the exact same setup as you. If, however, you need to develop on your OS directly, you can ask Zama for help.
in Docker
Here are the steps you can take in your Docker to try and fix issues:
If the problem persists at this point, you should ask for help. We're here and ready to assist!
X : training data By default, you should be able to pass: * numpy arrays * torch tensors * pandas DataFrame or Series
y (numpy.ndarray): The target data.
**kwargs: args for super().fit
Returns:
Any: The fitted model.
method post_processing
Apply post-processing to the predictions.
Args:
y_preds (numpy.ndarray): The predictions.
Returns:
numpy.ndarray: The post-processed predictions.
These models use a stack of linear layers and the activation function and the number of neurons in each layer is configurable. This approach is similar to what is available in Scikit-learn using the MLPClassifier/MLPRegressor classes. The built-in, fully connected neural network (FCNN) models train easily with a single call to .fit(), which will automatically quantize the weights and activations. These models use Quantization Aware Training, allowing good performance for low precision (down to 2-3 bit) weights and activations.
While NeuralNetClassifier and NeuralNetClassifier provide scikit-learn like models, their architecture is somewhat restricted in order to make training easy and robust. If you need more advanced models, you can convert custom neural networks as described in the FHE-friendly models documentation.
Good quantization parameter values are critical to make models respect FHE constraints. Weights and activations should be quantized to low precision (e.g. 2-4 bits). Furthermore, in cases of overflow, the sparsity of the network can be tuned as described below.
Example usage
To create an instance of a Fully Connected Neural Network you need to instantiate one of the NeuralNetClassifier and NeuralNetRegressor classes and configure a number of parameters that are passed to their constructor. Note that some parameters need to be prefixed by module__, while others don't. Basically, the parameters that are related to the model, i.e. the underlying nn.Module, must have the prefix. The parameters that are related to training options do not require the prefix.
The figure above shows, on the right, the Concrete-ML neural network, trained with Quantization Aware Training, in a FHE-compatible configuration. The figure compares this network to the floating point equivalent, trained with scikit-learn.
Architecture parameters
module__n_layers: number of layers in the FCNN, must be at least 1. Note that this is the total number of layers. For a single hidden layer NN model, set module__n_layers=2
module__n_outputs: number of outputs (classes or targets)
module__input_dim: dimensionality of the input
module__activation_function: can be one of the Torch activations (e.g. nn.ReLU, see the full list )
Quantization parameters
n_w_bits (default 3): number of bits for weights
n_a_bits (default 3): number of bits for activations and inputs
n_accum_bits (default 8): maximum accumulator bit-width that is desired. The implementation will attempt to keep accumulators under this bit-width through , i.e. setting some weights to zero
Training parameters (from Skorch)
max_epochs: The number of epochs to train the network (default 10)
verbose: Whether to log loss/metrics during training (default: False)
module__n_hidden_neurons_multiplier: The number of hidden neurons will be automatically set proportional to the dimensionality of the input (i.e. the value for module__input_dim). This parameter controls the proportionality factor and is set to 4 by default. This value gives good accuracy while avoiding accumulator overflow. See the pruning and quantization sections for more info.
Network input/output
When you have training data in the form of a NumPy array, and targets in a NumPy 1d array, you can set:
Class weights
You can give weights to each class to use in training. Note that this must be supported by the underlying PyTorch loss function.
Overflow errors
The n_hidden_neurons_multiplier parameter influences training accuracy as it controls the number of non-zero neurons that are allowed in each layer. Increasing n_hidden_neurons_multiplier improves accuracy, but should take into account precision limitations to avoid overflow in the accumulator. The default value is a good compromise that avoids overflow, in most cases, but you may want to change the value of this parameter to reduce the breadth of the network if you have overflow errors. A value of 1 should be completely safe with respect to overflow.
path_dir (str): the path to the directory where the circuit is saved
method load
Load the circuit.
method run
Run the model on the server over encrypted data.
Args:
serialized_encrypted_quantized_data (cnp.PublicArguments): the encrypted, quantized and serialized data
serialized_evaluation_keys (cnp.EvaluationKeys): the serialized evaluation keys
Returns:
cnp.PublicResult: the result of the model
class FHEModelDev
Dev API to save the model and then load and run the FHE circuit.
method __init__
Initialize the FHE API.
Args:
path_dir (str): the path to the directory where the circuit is saved
model (Any): the model to use for the FHE API
method save
Export all needed artifacts for the client and server.
Raises:
Exception: path_dir is not empty
class FHEModelClient
Client API to encrypt and decrypt FHE data.
method __init__
Initialize the FHE API.
Args:
path_dir (str): the path to the directory where the circuit is saved
key_dir (str): the path to the directory where the keys are stored
method deserialize_decrypt
Deserialize and decrypt the values.
Args:
serialized_encrypted_quantized_result (cnp.PublicArguments): the serialized, encrypted and quantized result
Returns:
numpy.ndarray: the decrypted and desarialized values
method deserialize_decrypt_dequantize
Deserialize, decrypt and dequantize the values.
Args:
serialized_encrypted_quantized_result (cnp.PublicArguments): the serialized, encrypted and quantized result
Returns:
numpy.ndarray: the decrypted (dequantized) values
method generate_private_and_evaluation_keys
Generate the private and evaluation keys.
Args:
force (bool): if True, regenerate the keys even if they already exist
method get_serialized_evaluation_keys
Get the serialized evaluation keys.
Returns:
cnp.EvaluationKeys: the evaluation keys
method load
Load the quantizers along with the FHE specs.
method quantize_encrypt_serialize
Quantize, encrypt and serialize the values.
Args:
x (numpy.ndarray): the values to quantize, encrypt and serialize
Returns:
cnp.PublicArguments: the quantized, encrypted and serialized values
Linear Models
Concrete-ML provides several of the most popular linear models for regression or classification that can be found in Scikit-learn:
Concrete-ML
scikit-learn
Using these models in FHE is extremely similar to what can be done with scikit-learn's , making it easy for data scientists who are used to this framework to get started with Concrete-ML.
Models are also compatible with some of scikit-learn's main workflows, such as Pipeline() or GridSearch().
Example
Here's an example of how to use this model in FHE on a simple data-set below. A more complete example can be found in the .
We can then plot the decision boundary of the classifier and then compare those results with a scikit-learn model executed in clear. The complete code can be found in the .
We can clearly observe the impact of quantization over the decision boundaries in the FHE model, separating the initial lines into broken lines with steps. However, this does not change the overall score as both models output the same accuracy (90%).
In fact, the quantization process may sometimes create some artifacts that could lead to a decrease in performance. Still, the impact of those artifacts is often minor when considering linear models as FHE models reach similar scores as their equivalent clear ones.
# check for gmake
which gmake
# If you don't have it, it will error out, install gmake
brew install make
# recheck, now you should have gmake
which gmake
cd concrete-ml
make setup_env
source .venv/bin/activate
source .venv/Scripts/activate
docker volume ls
# Here we have dev_venv sourced
(dev_venv) dev_user@8e299b32283c:/src$ make setup_env
deactivate
make sync_env
# Try to install the env normally
make setup_env
# If you are still having issues, sync the environment
make sync_env
# If you are still having issues on your OS, delete the venv:
rm -rf .venv
# And re-run the env setup
make setup_env
# Try to install the env normally
make setup_env
# If you are still having issues, sync the environment
make sync_env
# If you are still having issues in Docker, delete the venv:
rm -rf ~/dev_venv/*
# Disconnect from Docker
exit
# And relaunch, the venv will be reinstalled
make docker_start
# If you are still out of luck, force a rebuild which will also delete the volumes
make docker_rebuild
# And start Docker, which will reinstall the venv
make docker_start
import numpy
from tqdm import tqdm
from sklearn.datasets import make_classification
from sklearn.model_selection import train_test_split
from concrete.ml.sklearn import LogisticRegression
# Create the data for classification
X, y = make_classification(
n_features=2,
n_redundant=0,
n_informative=2,
random_state=2,
n_clusters_per_class=1,
n_samples=100,
)
# Retrieve train and test sets
X_train, X_test, y_train, y_test = train_test_split(X, y, test_size=0.4, random_state=42)
# Instantiate the model
model = LogisticRegression(n_bits=2)
# Fit the model
model.fit(X_train, y_train)
# Evaluate the model on the test set in clear
y_pred_clear = model.predict(X_test)
# Compile the model
model.compile(X_train)
# Perform the inference in FHE
# Note that here the encryption and decryption is done behind the scene.
# It is recommended to run this with a very small batch of
# examples first (e.g. N_TEST_FHE = 3)
N_TEST_FHE = 3
y_pred_fhe = numpy.array([
model.predict([sample], execute_in_fhe=True)[0]
for sample in tqdm(X_test[:N_TEST_FHE])
])
# Assert that FHE predictions are the same as the clear predictions
print(f"{(y_pred_fhe == y_pred_clear[:N_TEST_FHE]).sum()} "
f"examples over {N_TEST_FHE} have a FHE inference equal to the clear inference.")
# Output:
# 3 examples over 3 have a FHE inference equal to the clear inference
Using Torch
In addition to the built-in models, Concrete-ML supports generic machine learning models implemented with Torch, or exported as ONNX graphs.
The following example uses a simple QAT PyTorch model that implements a fully connected neural network with two hidden layers. Due to its small size, making this model respect FHE constraints is relatively easy.
Once the model is trained, calling the compile_brevitas_qat_model from Concrete-ML will automatically perform conversion and compilation of a QAT network. Here, 3-bit quantization is used for both the weights and activations.
The model can now be used to perform encrypted inference. Next, the test data is quantized:
and the encrypted inference run using either:
quantized_numpy_module.forward_and_dequant() to compute predictions in the clear, on quantized data and then de-quantize the result. The return value of this function contains the dequantized (float) output of running the model in the clear. Calling the forward function on the clear data is useful when debugging. The results in FHE will be the same as those on clear quantized data.
quantized_numpy_module.forward_fhe.encrypt_run_decrypt() to perform the FHE inference. In this case, dequantization is done in a second stage using quantized_numpy_module.dequantize_output().
Generic Quantization Aware Training import
While the example above shows how to import a Brevitas/PyTorch model, Concrete-ML also provides an option to import generic QAT models implemented either in PyTorch or through ONNX. Interestingly, deep learning models made with TensorFlow or Keras should be usable, by preliminary converting them to ONNX.
QAT models contain quantizers in the PyTorch graph. These quantizers ensure that the inputs to the Linear/Dense and Conv layers are quantized.
Suppose that n_bits_qat is the bit-width of activations and weights during the QAT process. To import a PyTorch QAT network, you can use the library function, passing import_qat=True:
Alternatively, if you want to import an ONNX model directly, please see . The also supports the import_qat parameter.
When importing QAT models using this generic pipeline, a representative calibration set should be given as quantization parameters in the model need to be inferred from the statistics of the values encountered during inference.
Supported operators and activations
Concrete-ML supports a variety of PyTorch operators that can be used to build fully connected or convolutional neural networks, with normalization and activation layers. Moreover, many element-wise operators are supported.
Operators
univariate operators
shape modifying operators
operators that take an encrypted input and unencrypted constants
Please note that Concrete-ML supports these operators but also the Quantization Aware Training equivalents from Brevitas.
brevitas.nn.QuantLinear
brevitas.nn.QuantConv2d
operators that can take both encrypted+unencrypted and encrypted+encrypted inputs
Quantizers
brevitas.nn.QuantIdentity
Activations
Note that the equivalent versions from torch.functional are also supported.
Production Deployment
Concrete-ML provides functionality to deploy FHE machine learning models in a client/server setting. The deployment workflow and model serving pattern is as follows:
Deployment
The training of the model and its compilation to FHE are performed on a development machine. Three different files are created when saving the model:
client.json contains the secure cryptographic parameters needed for the client to generate private and evaluation keys.
server.json contains the compiled model. This file is sufficient to run the model on a server.
serialized_processing.json contains the metadata about pre- and post-processing, such as quantization parameters to quantize the input and de-quantize the output.
The compiled model (server.zip) is deployed to a server and the cryptographic parameters (client.zip) along with the model meta data (serialized_processing.json) are shared with the clients.
Serving
The client obtains the cryptographic parameters (using client.zip) and generates a private encryption/decryption key as well as a set of public evaluation keys. The public evaluation keys are then sent to the server, while the secret key remains on the client.
The private data is then encrypted using serialized_processing.json by the client and sent to the server. Server-side, the FHE model inference is run on the encrypted inputs using the public evaluation keys.
The encrypted result is then returned by the server to the client, which decrypts it using its private key. Finally, the client performs any necessary post-processing of the decrypted result using serialized_processing.json.
Example notebook
For a complete example, see
concrete.ml.quantization.post_training
module concrete.ml.quantization.post_training
Post Training Quantization methods.
FHE Op-graph design
The section gave an overview of the conversion of a generic ONNX graph to a FHE compatible Concrete-ML op-graph. This section describes the implementation of operations in the Concrete-ML op-graph and the way floating point can be used in some parts of the op-graphs through table lookup operations.
Float vs. quantized operations
Concrete, the underlying implementation of TFHE that powers Concrete-ML, enables two types of operations on integers:
Using ONNX
In addition to Concrete-ML models and to , it is also possible to directly compile models. This can be particularly appealing, notably to import models trained with Keras.
ONNX models can be compiled by directly importing models that are already quantized with Quantization Aware Training (QAT). or by performing Post-Training Quantization (PTQ) with Concrete-ML.
Simple example
The following example shows how to compile an ONNX model using PTQ. The model was initially trained using Keras before being exported to ONNX. The training code is not shown here.
import brevitas.nn as qnn
import torch.nn as nn
import torch
N_FEAT = 12
n_bits = 3
class QATSimpleNet(nn.Module):
def __init__(self, n_hidden):
super().__init__()
self.quant_inp = qnn.QuantIdentity(bit_width=n_bits, return_quant_tensor=True)
self.fc1 = qnn.QuantLinear(N_FEAT, n_hidden, True, weight_bit_width=n_bits, bias_quant=None)
self.quant2 = qnn.QuantIdentity(bit_width=n_bits, return_quant_tensor=True)
self.fc2 = qnn.QuantLinear(n_hidden, n_hidden, True, weight_bit_width=3, bias_quant=None)
self.quant3 = qnn.QuantIdentity(bit_width=n_bits, return_quant_tensor=True)
self.fc3 = qnn.QuantLinear(n_hidden, 2, True, weight_bit_width=n_hidden, bias_quant=None)
def forward(self, x):
x = self.quant_inp(x)
x = self.quant2(torch.relu(self.fc1(x)))
x = self.quant3(torch.relu(self.fc2(x)))
x = self.fc3(x)
return x
from concrete.ml.torch.compile import compile_brevitas_qat_model
import numpy
torch_input = torch.randn(100, N_FEAT)
torch_model = QATSimpleNet(30)
quantized_numpy_module = compile_brevitas_qat_model(
torch_model, # our model
torch_input, # a representative input-set to be used for both quantization and compilation
n_bits = n_bits,
)
This example uses Post-Training Quantization, i.e. the quantization is not performed during training. Thus this model would not have good performance in FHE. Quantization Aware Training should be added by the model developer and importing QAT ONNX models can be done as shown below.
While Keras was used in this example, it is not officially supported as additional work is needed to test all of Keras' types of layer and models.
Quantization Aware Training
QAT models contain quantizers in the ONNX graph. These quantizers ensure that the inputs to the Linear/Dense and Conv layers are quantized. Since these QAT models have quantizers that are configured during training to a specific number of bits, the ONNX graph will need to be imported using the same settings:
Supported operators
The following operators are supported for evaluation and conversion to an equivalent FHE circuit. Other operators were not implemented either due to FHE constraints, or because they are rarely used in PyTorch activations or scikit-learn models.
import numpy
import onnx
import tensorflow
import tf2onnx
from concrete.ml.torch.compile import compile_onnx_model
from concrete.numpy.compilation import Configuration
class FC(tensorflow.keras.Model):
"""A fully-connected model."""
def __init__(self):
super().__init__()
hidden_layer_size = 10
output_size = 5
self.dense1 = tensorflow.keras.layers.Dense(
hidden_layer_size,
activation=tensorflow.nn.relu,
)
self.dense2 = tensorflow.keras.layers.Dense(output_size, activation=tensorflow.nn.relu6)
self.flatten = tensorflow.keras.layers.Flatten()
def call(self, inputs):
"""Forward function."""
x = self.flatten(inputs)
x = self.dense1(x)
x = self.dense2(x)
return self.flatten(x)
n_bits = 6
input_output_feature = 2
input_shape = (input_output_feature,)
num_inputs = 1
n_examples = 5000
# Define the Keras model
keras_model = FC()
keras_model.build((None,) + input_shape)
keras_model.compute_output_shape(input_shape=(None, input_output_feature))
# Create random input
input_set = numpy.random.uniform(-100, 100, size=(n_examples, *input_shape))
# Convert to ONNX
tf2onnx.convert.from_keras(keras_model, opset=14, output_path="tmp.model.onnx")
onnx_model = onnx.load("tmp.model.onnx")
onnx.checker.check_model(onnx_model)
# Compile
quantized_numpy_module = compile_onnx_model(
onnx_model, input_set, n_bits=2
)
# Create test data from the same distribution and quantize using
# learned quantization parameters during compilation
x_test = tuple(numpy.random.uniform(-100, 100, size=(1, *input_shape)) for _ in range(num_inputs))
qtest = quantized_numpy_module.quantize_input(x_test)
y_clear = quantized_numpy_module(*qtest)
y_fhe = quantized_numpy_module.forward_fhe.encrypt_run_decrypt(*qtest)
print("Execution in clear: ", y_clear)
print("Execution in FHE: ", y_fhe)
print("Equality: ", numpy.sum(y_clear == y_fhe), "over", numpy.size(y_fhe), "values")
n_bits_qat = 3 # number of bits for weights and activations during training
quantized_numpy_module = compile_onnx_model(
onnx_model,
input_set,
n_bits=n_bits_qat,
)
Global Variables
ONNX_OPS_TO_NUMPY_IMPL
DEFAULT_MODEL_BITS
ONNX_OPS_TO_QUANTIZED_IMPL
class ONNXConverter
Base ONNX to Concrete ML computation graph conversion class.
This class provides a method to parse an ONNX graph and apply several transformations. First, it creates QuantizedOps for each ONNX graph op. These quantized ops have calibrated quantizers that are useful when the operators work on integer data or when the output of the ops is the output of the encrypted program. For operators that compute in float and will be merged to TLUs, these quantizers are not used. Second, this converter creates quantized tensors for initializer and weights stored in the graph.
This class should be sub-classed to provide specific calibration and quantization options depending on the usage (Post-training quantization vs Quantization Aware training).
Arguments:
n_bits (int, Dict[str, int]): number of bits for quantization, can be a single value or a dictionary with the following keys : - "op_inputs" and "op_weights" (mandatory) - "model_inputs" and "model_outputs" (optional, default to 5 bits). When using a single integer for n_bits, its value is assigned to "op_inputs" and "op_weights" bits. The maximum between this value and a default value (5) is then assigned to the number of "model_inputs" "model_outputs". This default value is a compromise between model accuracy and runtime performance in FHE. "model_outputs" gives the precision of the final network's outputs, while "model_inputs" gives the precision of the network's inputs. "op_inputs" and "op_weights" both control the quantization for inputs and weights of all layers.
y_model (NumpyModule): Model in numpy.
is_signed (bool): Whether the weights of the layers can be signed. Currently, only the weights can be signed.
method __init__
property n_bits_model_inputs
Get the number of bits to use for the quantization of the first layer's output.
Returns:
n_bits (int): number of bits for input quantization
property n_bits_model_outputs
Get the number of bits to use for the quantization of the last layer's output.
Returns:
n_bits (int): number of bits for output quantization
property n_bits_op_inputs
Get the number of bits to use for the quantization of any operators' inputs.
Returns:
n_bits (int): number of bits for the quantization of the operators' inputs
property n_bits_op_weights
Get the number of bits to use for the quantization of any constants (usually weights).
Returns:
n_bits (int): number of bits for quantizing constants used by operators
method quantize_module
Quantize numpy module.
Following https://arxiv.org/abs/1712.05877 guidelines.
Args:
*calibration_data (numpy.ndarray): Data that will be used to compute the bounds, scales and zero point values for every quantized object.
Returns:
QuantizedModule: Quantized numpy module
class PostTrainingAffineQuantization
Post-training Affine Quantization.
Create the quantized version of the passed numpy module.
Args:
n_bits (int, Dict): Number of bits to quantize the model. If an int is passed for n_bits, the value will be used for activation, inputs and weights. If a dict is passed, then it should contain "model_inputs", "op_inputs", "op_weights" and "model_outputs" keys with corresponding number of quantization bits for: - model_inputs : number of bits for model input - op_inputs : number of bits to quantize layer input values - op_weights: learned parameters or constants in the network - model_outputs: final model output quantization bits
numpy_model (NumpyModule): Model in numpy.
is_signed: Whether the weights of the layers can be signed. Currently, only the weights can be signed.
Returns:
QuantizedModule: A quantized version of the numpy model.
method __init__
property n_bits_model_inputs
Get the number of bits to use for the quantization of the first layer's output.
Returns:
n_bits (int): number of bits for input quantization
property n_bits_model_outputs
Get the number of bits to use for the quantization of the last layer's output.
Returns:
n_bits (int): number of bits for output quantization
property n_bits_op_inputs
Get the number of bits to use for the quantization of any operators' inputs.
Returns:
n_bits (int): number of bits for the quantization of the operators' inputs
property n_bits_op_weights
Get the number of bits to use for the quantization of any constants (usually weights).
Returns:
n_bits (int): number of bits for quantizing constants used by operators
method quantize_module
Quantize numpy module.
Following https://arxiv.org/abs/1712.05877 guidelines.
Args:
*calibration_data (numpy.ndarray): Data that will be used to compute the bounds, scales and zero point values for every quantized object.
Returns:
QuantizedModule: Quantized numpy module
class PostTrainingQATImporter
Converter of Quantization Aware Training networks.
This class provides specific configuration for QAT networks during ONNX network conversion to Concrete ML computation graphs.
method __init__
property n_bits_model_inputs
Get the number of bits to use for the quantization of the first layer's output.
Returns:
n_bits (int): number of bits for input quantization
property n_bits_model_outputs
Get the number of bits to use for the quantization of the last layer's output.
Returns:
n_bits (int): number of bits for output quantization
property n_bits_op_inputs
Get the number of bits to use for the quantization of any operators' inputs.
Returns:
n_bits (int): number of bits for the quantization of the operators' inputs
property n_bits_op_weights
Get the number of bits to use for the quantization of any constants (usually weights).
Returns:
n_bits (int): number of bits for quantizing constants used by operators
method quantize_module
Quantize numpy module.
Following https://arxiv.org/abs/1712.05877 guidelines.
Args:
*calibration_data (numpy.ndarray): Data that will be used to compute the bounds, scales and zero point values for every quantized object.
Returns:
QuantizedModule: Quantized numpy module
arithmetic operations: the addition of two encrypted values and multiplication of encrypted values with clear scalars. These are used, for example, in dot-products, matrix multiplication (linear layers) and convolution.
table lookup operations (TLU): using an encrypted value as an index, return the value of a lookup table at that index. This is implemented using Programmable Bootstrapping. This operation is used to perform any non-linear computation such as activation functions, quantization and normalization.
Since machine learning models use floating point inputs and weights, they first need to be converted to integers using quantization.
Alternatively, it is possible to use a table lookup to avoid the quantization of the entire graph, by converting floating-point ONNX subgraphs into lambdas and computing their corresponding lookup tables to be evaluated directly in FHE. This operator-fusion technique only requires the input and output of the lambdas to be integers.
For example, in the following graph there is a single input, which must be an encrypted integer tensor. The following series of univariate functions is then fed into a matrix multiplication (MatMul) and fused into a single table lookup with integer inputs and outputs.
ONNX operations
Concrete-ML implements ONNX operations using Concrete-Numpy, which can handle floating point operations, as long as they can be fused to an integer lookup table. The ONNX operations implementations are based on the QuantizedOp class.
There are two modes of creation of a single table lookup for a chain of ONNX operations:
float mode: when the operation can be fused
mixed float/integer: when the ONNX operation needs to perform arithmetic operations
Thus, QuantizedOp instances may need to quantize their inputs or the result of their computation, depending on their position in the graph.
The QuantizedOp class provides a generic implementation of an ONNX operation, including the quantization of inputs and outputs, with the computation implemented in NumPy in ops_impl.py. It is possible to picture at the architecture of the QuantizedOp as the following structure:
This figure shows that the QuantizedOp has a body that implements the computation of the operation, following the ONNX spec. The operation's body can take either integer or float inputs and can output float or integer values. Two quantizers are attached to the operation: one that takes float inputs and produces integer inputs and one that does the same for the output.
Operations that can fuse to a TLU
Depending on the position of the op in the graph and its inputs, the QuantizedOp can be fully fused to a TLU.
Many ONNX ops are trivially univariate, as they multiply variable inputs with constants or apply univariate functions such as ReLU, Sigmoid, etc. This includes operations between the input and the MatMul in the graph above (subtraction, comparison, multiplication, etc. between inputs and constants).
Operations that work on integers
Operations, such as matrix multiplication of encrypted inputs with a constant matrix or convolution with constant weights, require that the encrypted inputs be integers. In this case, the input quantizer of the QuantizedOp is applied. These types of operations are implemented with a class that derives from QuantizedOp and implements q_impl, such as QuantizedGemm and QuantizedConv.
Operations that produce graph outputs
Finally, some operations produce graph outputs, which must be integers. These operations need to quantize their outputs as follows:
The diagram above shows that both float ops and integer ops need to quantize their outputs to integers, when placed at the end of the graph.
Putting it all together
To chain the operation types described above following the ONNX graph, Concrete-ML constructs a function that calls the q_impl of the QuantizedOp instances in the graph in sequence, and uses Concrete-Numpy to trace the execution and compile to FHE. Thus, in this chain of function calls, all groups of that instruction that operate in floating point will be fused to TLUs. In FHE, this lookup table is computed with a PBS.
The red contours show the groups of elementary Concrete-Numpy instructions that will be converted to TLUs.
Note that the input is slightly different from the QuantizedOp. Since the encrypted function takes integers as inputs, the input needs to be de-quantized first.
Implementing a QuantizedOp
QuantizedOp is the base class for all ONNX-quantized operators. It abstracts away many things to allow easy implementation of new quantized ops.
Determining if the operation can be fused
The QuantizedOp class exposes a function can_fuse that
helps to determine the type of implementation that will be traced
determines whether operations further in the graph, that depend on the results of this operation, can fuse
In most cases, ONNX ops have a single variable input and one or more constant inputs.
When the op implements elementwise operations between the inputs and constants (addition, subtract, multiplication, etc), the operation can be fused to a TLU. Thus, by default in QuantizedOp, the can_fuse function returns True.
When the op implements operations that mix the various scalars in the input encrypted tensor, the operation cannot fuse, as table lookups are univariate. Thus, operations such as QuantizedGemm, QuantizedConv return False in can_fuse.
Some operations may be found in both settings above. A mechanism is implemented in Concrete-ML to determine if the inputs of a QuantizedOp are produced by a unique integer tensor. Therefore, the can_fuse function of some QuantizedOp types (addition, subtraction) will allow fusion to take place if both operands are produced by a unique integer tensor:
Case 1: A floating point version of the op is sufficient
You can check ops_impl.py to see how some operations are implemented in NumPy. The declaration convention for these operations is as follows:
The required inputs should be positional arguments only before the /, which marks the limit of the positional arguments
The optional inputs should be positional or keyword arguments between the / and *, which marks the limits of positional or keyword arguments
The operator attributes should be keyword arguments only after the *
The proper use of positional/keyword arguments is required to allow the QuantizedOp class to properly populate metadata automatically. It uses Python inspect modules and stores relevant information for each argument related to its positional/keyword status. This allows using the Concrete-NumPy implementation as specifications for QuantizedOp, which removes some data duplication and allows having a single source of truth for QuantizedOp and ONNX-NumPy implementations.
In that case (unless the quantized implementation requires special handling like QuantizedGemm), you can just set _impl_for_op_named to the name of the ONNX op for which the quantized class is implemented (this uses the mapping ONNX_OPS_TO_NUMPY_IMPL in onnx_utils.py to get the correct implementation).
Case 2: An integer implementation of the op is necessary
Providing an integer implementation requires sub-classing QuantizedOp to create a new operation. This sub-class must override q_impl in order to provide an integer implementation. QuantizedGemm is an example of such a case where quantized matrix multiplication requires proper handling of scales and zero points. The q_impl of that class reflects this.
In the body of q_impl, in order to obtain quantized integer values you can use the _prepare_inputs_with_constants function as such:
Here, prepared_inputs will contain one or more QuantizedArray of which the qvalues are the quantized integers.
Once the required integer processing code is implemented, the output of the q_impl function must be implemented as a single QuantizedArray. Most commonly, this is built using the de-quantized results of the processing done in q_impl.
Case 3: Both a floating point and an integer implementation are necessary
In this case, in q_impl you can check whether the current operation can be fused by calling self.can_fuse(). You can then have both a floating point and an integer implementation. The traced execution path will depend on can_fuse():
numpy.ndarray: the output values for the provided calibration samples.
method call_impl
Call self.impl to centralize mypy bug workaround.
Args:
*inputs (numpy.ndarray): real valued inputs.
**attrs: the QuantizedOp attributes.
Returns:
numpy.ndarray: return value of self.impl
method can_fuse
Determine if the operator impedes graph fusion.
This function shall be overloaded by inheriting classes to test self._int_input_names, to determine whether the operation can be fused to a TLU or not. For example an operation that takes inputs produced by a unique integer tensor can be fused to a TLU. Example: f(x) = x * (x + 1) can be fused. A function that does f(x) = x * (x @ w + 1) can't be fused.
Returns:
bool: whether this instance of the QuantizedOp produces Concrete Numpy code that can be fused to TLUs
classmethod must_quantize_input
Determine if an input must be quantized.
Quantized ops and numpy onnx ops take inputs and attributes. Inputs can be either constant or variable (encrypted). Note that this does not handle attributes, which are handled by QuantizedOp classes separately in their constructor.
Args:
input_name_or_idx (int): Index of the input to check.
Returns:
result (bool): Whether the input must be quantized (must be a QuantizedArray) or if it stays as a raw numpy.array read from ONNX.
method prepare_output
Quantize the output of the activation function.
The calibrate method needs to be called with sample data before using this function.
Args:
qoutput_activation (numpy.ndarray): Output of the activation function.
Returns:
QuantizedArray: Quantized output.
method q_impl
Execute the quantized forward.
Args:
*q_inputs (QuantizedArray): Quantized inputs.
**attrs: the QuantizedOp attributes.
Returns:
QuantizedArray: The returned quantized value.
class QuantizedOpUnivariateOfEncrypted
An univariate operator of an encrypted value.
This operation is not really operating as a quantized operation. It is useful when the computations get fused into a TLU, as in e.g. Act(x) = x || (x + 42)).
method __init__
property op_type
Get the type of this operation.
Returns:
op_type (str): The type of this operation, in the ONNX referential
method calibrate
Create corresponding QuantizedArray for the output of the activation function.
numpy.ndarray: the output values for the provided calibration samples.
method call_impl
Call self.impl to centralize mypy bug workaround.
Args:
*inputs (numpy.ndarray): real valued inputs.
**attrs: the QuantizedOp attributes.
Returns:
numpy.ndarray: return value of self.impl
method can_fuse
Determine if this op can be fused.
This operation can be fused and computed in float when a single integer tensor generates both the operands. For example in the formula: f(x) = x || (x + 1) where x is an integer tensor.
Returns:
bool: Can fuse
classmethod must_quantize_input
Determine if an input must be quantized.
Quantized ops and numpy onnx ops take inputs and attributes. Inputs can be either constant or variable (encrypted). Note that this does not handle attributes, which are handled by QuantizedOp classes separately in their constructor.
Args:
input_name_or_idx (int): Index of the input to check.
Returns:
result (bool): Whether the input must be quantized (must be a QuantizedArray) or if it stays as a raw numpy.array read from ONNX.
method prepare_output
Quantize the output of the activation function.
The calibrate method needs to be called with sample data before using this function.
Args:
qoutput_activation (numpy.ndarray): Output of the activation function.
Returns:
QuantizedArray: Quantized output.
method q_impl
Execute the quantized forward.
Args:
*q_inputs (QuantizedArray): Quantized inputs.
**attrs: the QuantizedOp attributes.
Returns:
QuantizedArray: The returned quantized value.
Tree-based Models
Concrete-ML provides several of the most popular classification and regression tree models that can be found in Scikit-learn:
Concrete-ML
scikit-learn
In addition to support for scikit-learn, Concrete-ML also supports 's XGBClassifier:
Concrete-ML
XGboost
Example
Here's an example of how to use this model in FHE on a popular data-set using some of scikit-learn's pre-processing tools. A more complete example can be found in the .
Using the above example, we can then plot how the model classifies the inputs and then compare those results with the XGBoost model executed in clear. A 6-bits model is also given in order to better understand the impact of quantization on classification. Similar plots can be found in the .
This graph shows the impact of quantization over the decision boundaries in the Concrete-ML FHE decision tree models. In the 3-bits model, only a rough, highly-discrete decision function is observed. This results in a small decrease of accuracy of about 7% compared to the initial XGBoost classifier. Besides, using 6-bits of quantization makes the model reach 93% accuracy, drastically reducing this difference to only 1.7 percentage points.
In fact, the quantization process may sometimes create some artifacts that could lead to a decrease in performance. Still, as the quantization is done individually on each input feature, the artifacts are minor when considering small tree-based models with 5-6 bits quantization. Thus, FHE tree-based models reach similar scores as their equivalent floating point ones.
The following graph shows that using 5-6 bits of quantization is usually sufficient to reach the performance of a non-quantized XGBoost model on floating point data. The metrics plotted are accuracy and F1-score on the spambase data-set.
Step-by-Step Guide
This section includes a complete example of converting a neural network to Quantization Aware Training (QAT). This tutorial uses PyTorch and Brevitas to train a simple network on a synthetic data-set. You can find the demo of the final network in the . To see how to apply these network design principles for a real-world data-set, please see the .
For a more formal description of the usage of Brevitas to build FHE-compatible neural networks, please see the .
Comparison of clasification decision boundaries between FHE and plaintext models
XGBoost n_bits comparison
from sklearn.datasets import load_breast_cancer
from sklearn.decomposition import PCA
from sklearn.model_selection import GridSearchCV, train_test_split
from sklearn.pipeline import Pipeline
from sklearn.preprocessing import StandardScaler
from concrete.ml.sklearn.xgb import XGBClassifier
# Get data-set and split into train and test
X, y = load_breast_cancer(return_X_y=True)
# Split the train and test set
X_train, X_test, y_train, y_test = train_test_split(X, y, test_size=0.2, random_state=0)
# Define our model
model = XGBClassifier(n_jobs=1, n_bits=3)
# Define the pipeline
# We will normalize the data and apply a PCA before fitting the model
pipeline = Pipeline(
[("standard_scaler", StandardScaler()), ("pca", PCA(random_state=0)), ("model", model)]
)
# Define the parameters to tune
param_grid = {
"pca__n_components": [2, 5, 10, 15],
"model__max_depth": [2, 3, 5],
"model__n_estimators": [5, 10, 20],
}
# Instantiate the grid search with 5-fold cross validation on all available cores
grid = GridSearchCV(pipeline, param_grid, cv=5, n_jobs=-1, scoring="accuracy")
# Launch the grid search
grid.fit(X_train, y_train)
# Print the best parameters found
print(f"Best parameters found: {grid.best_params_}")
# Output:
# Best parameters found: {'model__max_depth': 5, 'model__n_estimators': 10, 'pca__n_components': 5}
# Currently we only focus on model inference in FHE
# The data transformation will be done in clear (client machine)
# while the model inference will be done in FHE on a server.
# The pipeline can be split into 2 parts:
# 1. data transformation
# 2. estimator
best_pipeline = grid.best_estimator_
data_transformation_pipeline = best_pipeline[:-1]
model = best_pipeline[-1]
# Transform test set
X_train_transformed = data_transformation_pipeline.transform(X_train)
X_test_transformed = data_transformation_pipeline.transform(X_test)
# Evaluate the model on the test set in clear
y_pred_clear = model.predict(X_test_transformed)
print(f"Test accuracy in clear: {(y_pred_clear == y_test).mean():0.2f}")
# Output:
# Test accuracy: 0.98
# Compile the model to FHE
model.compile(X_train_transformed)
# Perform the inference in FHE
# Warning: this will take a while. It is recommended to run this with a very small batch of
# example first (e.g. N_TEST_FHE = 1)
# Note that here the encryption and decryption is done behind the scene.
N_TEST_FHE = 1
y_pred_fhe = model.predict(X_test_transformed[:N_TEST_FHE], execute_in_fhe=True)
# Assert that FHE predictions are the same as the clear predictions
print(f"{(y_pred_fhe == y_pred_clear[:N_TEST_FHE]).sum()} "
f"examples over {N_TEST_FHE} have a FHE inference equal to the clear inference.")
# Output:
# 1 examples over 1 have a FHE inference equal to the clear inference
DEFAULT_MODEL_BITS
constant_inputs
(Optional[Union[Dict[str, Any], Dict[int, Any]]]): The constant tensors that are inputs to this op
input_quant_opts (QuantizationOptions): Input quantizer options, determine the quantization that is applied to input tensors (that are not constants)
This example shows how to train a fully-connected neural network on a synthetic 2D data-set with a checkerboard grid pattern of 100 x 100 points. The data is split into 9500 training and 500 test samples.
In PyTorch, using standard layers, this network would look as follows:
Once trained, this network can be imported using the compile_torch_model function. This function uses simple Post-Training Quantization.
The network was trained using different numbers of neurons in the hidden layers, and quantized using 3-bits weights and activations. The mean accumulator size shown below was extracted using the Virtual Library.
neurons
10
30
100
fp32 accuracy
68.70%
83.32%
88.06%
3bit accuracy
56.44%
55.54%
56.50%
mean accumulator size
This shows that the fp32 accuracy and accumulator size increases with the number of hidden neurons, while the 3-bit accuracy remains low irrespective of to the number of neurons. While all the configurations tried here were FHE-compatible (accumulator < 8 bits), it is sometimes preferable to have a lower accumulator size in order for the inference time to be faster.
The accumulator size is determined by Concrete-Numpy as being the maximum bit-width encountered anywhere in the encrypted circuit
Pruning using Torch
Considering that FHE only works with limited integer precision, there is a risk of overflowing in the accumulator, resulting in unpredictable results.
To understand how to overcome this limitation, consider a scenario where 2 bits are used for weights and layer inputs/outputs. The Linear layer computes a dot product between weights and inputs y=∑iwixi. With 2 bits, no overflow can occur during the computation of the Linear layer as long the number of neurons does not exceed 14, i.e. the sum of 14 products of 2-bit numbers does not exceed 7 bits.
By default, Concrete-ML uses symmetric quantization for model weights, with values in the interval [−2nbits−1,2nbits−1−1]. For example, for nbits=2 the possible values are [−2,−1,0,1], for nbits=3 the values can be [−4,−3,−2,−1,0,1,2,3].
However, in a typical setting, the weights will not all have the maximum or minimum values (e.g. −2nbits−1). Instead, weights typically have a normal distribution around 0, which is one of the motivating factors for their symmetric quantization. A symmetric distribution and many zero-valued weights are desirable because opposite sign weights can cancel each other out and zero weights do not increase the accumulator size.
This can be leveraged to train a network with more neurons, while not overflowing the accumulator, using a technique called pruning, where the developer can impose a number of zero-valued weights. Torch provides support for pruning out of the box.
The following code shows how to use pruning in the previous example:
Results with PrunedSimpleNet, a pruned version of the SimpleNet with 100 neurons on the hidden layers, are given below:
non-zero neurons
10
30
fp32 accuracy
82.50%
88.06%
3bit accuracy
57.74%
57.82%
mean accumulator size
6.6
6.8
This shows that the fp32 accuracy has been improved while maintaining constant mean accumulator size.
When pruning a larger neural network during training, it is easier to obtain a low bit-width accumulator while maintaining better final accuracy. Thus, pruning is more robust than training a similar smaller network.
Quantization Aware Training
While pruning helps maintain the post-quantization level of accuracy in low-precision settings, it does not help maintain accuracy when quantizing from floating point models. The best way to guarantee accuracy is to use QAT (read more in the quantization documentation).
In this example, QAT is done using Brevitas, changing Linear layers to QuantLinear and adding quantizers on the inputs of linear layers using QuantIdentity.
The QAT import tool in Concrete-ML is a work in progress. While it has been tested with some networks built with Brevitas, it is possible to use other tools to obtain QAT networks.
Training this network with 30 out of 100 total non-zero neurons gives good accuracy while being FHE-compatible (accumulator size < 8 bits).
non-zero neurons
30
3bit accuracy brevitas
95.4%
3bit accuracy in Concrete-ML
92.4%
accumulator size
7
The PyTorch QAT training loop is the same as the standard floating point training loop, but hyper-parameters such as learning rate might need to be adjusted.
Quantization Aware Training is somewhat slower than normal training. QAT introduces quantization during both the forward and backward passes. The quantization process is inefficient on GPUs as its computational intensity is low with respect to data transfer time.
from torch import nn
import torch
N_FEAT = 2
class SimpleNet(nn.Module):
"""Simple MLP with PyTorch"""
def __init__(self, n_hidden=30):
super().__init__()
self.fc1 = nn.Linear(in_features=N_FEAT, out_features=n_hidden)
self.fc2 = nn.Linear(in_features=n_hidden, out_features=n_hidden)
self.fc3 = nn.Linear(in_features=n_hidden, out_features=2)
def forward(self, x):
"""Forward pass."""
x = torch.relu(self.fc1(x))
x = torch.relu(self.fc2(x))
x = self.fc3(x)
return x
import torch.nn.utils.prune as prune
class PrunedSimpleNet(SimpleNet):
"""Simple MLP with PyTorch"""
def prune(self, max_non_zero, enable):
# Linear layer weight has dimensions NumOutputs x NumInputs
for layer in self.named_modules():
if isinstance(layer, nn.Linear):
num_zero_weights = (layer.weight.shape[1] - max_non_zero) * layer.weight.shape[0]
if num_zero_weights <= 0:
continue
if enable:
prune.l1_unstructured(layer, "weight", amount=num_zero_weights)
else:
prune.remove(layer, "weight")
import brevitas.nn as qnn
from brevitas.core.bit_width import BitWidthImplType
from brevitas.core.quant import QuantType
from brevitas.core.restrict_val import FloatToIntImplType, RestrictValueType
from brevitas.core.scaling import ScalingImplType
from brevitas.core.zero_point import ZeroZeroPoint
from brevitas.inject import ExtendedInjector
from brevitas.quant.solver import ActQuantSolver, WeightQuantSolver
from dependencies import value
# Configure quantization options
class CommonQuant(ExtendedInjector):
bit_width_impl_type = BitWidthImplType.CONST
scaling_impl_type = ScalingImplType.CONST
restrict_scaling_type = RestrictValueType.FP
zero_point_impl = ZeroZeroPoint
float_to_int_impl_type = FloatToIntImplType.ROUND
scaling_per_output_channel = False
narrow_range = True
signed = True
@value
def quant_type(bit_width):
if bit_width is None:
return QuantType.FP
elif bit_width == 1:
return QuantType.BINARY
else:
return QuantType.INT
# Quantization options for weights/activations
class CommonWeightQuant(CommonQuant, WeightQuantSolver):
scaling_const = 1.0
signed = True
class CommonActQuant(CommonQuant, ActQuantSolver):
min_val = -1.0
max_val = 1.0
class QATPrunedSimpleNet(nn.Module):
def __init__(self, n_hidden):
super(QATPrunedSimpleNet, self).__init__()
n_bits = 3
self.quant_inp = qnn.QuantIdentity(
act_quant=CommonActQuant,
bit_width=n_bits,
return_quant_tensor=True,
)
self.fc1 = qnn.QuantLinear(
N_FEAT,
n_hidden,
True,
weight_quant=CommonWeightQuant,
weight_bit_width=n_bits,
bias_quant=None,
)
self.q1 = qnn.QuantIdentity(
act_quant=CommonActQuant, bit_width=n_bits, return_quant_tensor=True
)
self.fc2 = qnn.QuantLinear(
n_hidden,
n_hidden,
True,
weight_quant=CommonWeightQuant,
weight_bit_width=3,
bias_quant=None
)
self.q2 = qnn.QuantIdentity(
act_quant=CommonActQuant, bit_width=n_bits, return_quant_tensor=True
)
self.fc3 = qnn.QuantLinear(
n_hidden,
2,
True,
weight_quant=CommonWeightQuant,
weight_bit_width=n_hidden,
bias_quant=None,
)
for m in self.modules():
if isinstance(m, qnn.QuantLinear):
torch.nn.init.uniform_(m.weight.data, -1, 1)
def forward(self, x):
x = self.quant_inp(x)
x = self.q1(torch.relu(self.fc1(x)))
x = self.q2(torch.relu(self.fc2(x)))
x = self.fc3(x)
return x
def prune(self, max_non_zero, enable):
# Linear layer weight has dimensions NumOutputs x NumInputs
for name, layer in self.named_modules():
if isinstance(layer, nn.Linear):
num_zero_weights = (layer.weight.shape[1] - max_non_zero) * layer.weight.shape[0]
if num_zero_weights <= 0:
continue
if enable:
print(f"Pruning layer {name} factor {num_zero_weights}")
prune.l1_unstructured(layer, "weight", amount=num_zero_weights)
else:
prune.remove(layer, "weight")
6.6
6.9
7.4
class PoissonRegressor
A Poisson regression model with FHE.
method __init__
property fhe_circuit
Get the FHE circuit.
Returns:
Circuit: the FHE circuit
property input_quantizers
Get the input quantizers.
Returns:
List[QuantizedArray]: the input quantizers
property onnx_model
property output_quantizers
Get the input quantizers.
Returns:
List[QuantizedArray]: the input quantizers
property quantize_input
Get the input quantization function.
Returns:
Callable : function that quantizes the input
method fit
Fit the GLM regression quantized model.
Args:
X : The training data, which can be: * numpy arrays * torch tensors * pandas DataFrame or Series
y (numpy.ndarray): The target data.
*args: The arguments to pass to the sklearn linear model.
**kwargs: The keyword arguments to pass to the sklearn linear model.
method post_processing
Post-processing the predictions.
Args:
y_preds (numpy.ndarray): The predictions to post-process.
already_dequantized (bool): Wether the inputs were already dequantized or not. Default to False.
Returns:
numpy.ndarray: The post-processed predictions.
method predict
Predict on user data.
Predict on user data using either the quantized clear model, implemented with tensors, or, if execute_in_fhe is set, using the compiled FHE circuit.
Args:
X (numpy.ndarray): The input data.
execute_in_fhe (bool): Whether to execute the inference in FHE. Default to False.
Returns:
numpy.ndarray: The model's predictions.
class GammaRegressor
A Gamma regression model with FHE.
method __init__
property fhe_circuit
Get the FHE circuit.
Returns:
Circuit: the FHE circuit
property input_quantizers
Get the input quantizers.
Returns:
List[QuantizedArray]: the input quantizers
property onnx_model
property output_quantizers
Get the input quantizers.
Returns:
List[QuantizedArray]: the input quantizers
property quantize_input
Get the input quantization function.
Returns:
Callable : function that quantizes the input
method fit
Fit the GLM regression quantized model.
Args:
X : The training data, which can be: * numpy arrays * torch tensors * pandas DataFrame or Series
y (numpy.ndarray): The target data.
*args: The arguments to pass to the sklearn linear model.
**kwargs: The keyword arguments to pass to the sklearn linear model.
method post_processing
Post-processing the predictions.
Args:
y_preds (numpy.ndarray): The predictions to post-process.
already_dequantized (bool): Wether the inputs were already dequantized or not. Default to False.
Returns:
numpy.ndarray: The post-processed predictions.
method predict
Predict on user data.
Predict on user data using either the quantized clear model, implemented with tensors, or, if execute_in_fhe is set, using the compiled FHE circuit.
Args:
X (numpy.ndarray): The input data.
execute_in_fhe (bool): Whether to execute the inference in FHE. Default to False.
Returns:
numpy.ndarray: The model's predictions.
class TweedieRegressor
A Tweedie regression model with FHE.
method __init__
property fhe_circuit
Get the FHE circuit.
Returns:
Circuit: the FHE circuit
property input_quantizers
Get the input quantizers.
Returns:
List[QuantizedArray]: the input quantizers
property onnx_model
property output_quantizers
Get the input quantizers.
Returns:
List[QuantizedArray]: the input quantizers
property quantize_input
Get the input quantization function.
Returns:
Callable : function that quantizes the input
method fit
Fit the GLM regression quantized model.
Args:
X : The training data, which can be: * numpy arrays * torch tensors * pandas DataFrame or Series
y (numpy.ndarray): The target data.
*args: The arguments to pass to the sklearn linear model.
**kwargs: The keyword arguments to pass to the sklearn linear model.
method post_processing
Post-processing the predictions.
Args:
y_preds (numpy.ndarray): The predictions to post-process.
already_dequantized (bool): Wether the inputs were already dequantized or not. Default to False.
Returns:
numpy.ndarray: The post-processed predictions.
method predict
Predict on user data.
Predict on user data using either the quantized clear model, implemented with tensors, or, if execute_in_fhe is set, using the compiled FHE circuit.
Args:
X (numpy.ndarray): The input data.
execute_in_fhe (bool): Whether to execute the inference in FHE. Default to False.
Returns:
numpy.ndarray: The model's predictions.
concrete.ml.sklearn.linear_model
module concrete.ml.sklearn.linear_model
Implement sklearn linear model.
class LinearRegression
A linear regression model with FHE.
Arguments:
n_bits (int): default is 2.
use_sum_workaround (bool): indicate if the sum workaround should be used or not. This
For more details on LinearRegression please refer to the scikit-learn documentation: https://scikit-learn.org/stable/modules/generated/sklearn.linear_model.LinearRegression.html
method __init__
property fhe_circuit
Get the FHE circuit.
Returns:
Circuit: the FHE circuit
property input_quantizers
Get the input quantizers.
Returns:
List[QuantizedArray]: the input quantizers
property onnx_model
Get the ONNX model.
.. # noqa: DAR201
Returns:
onnx.ModelProto: the ONNX model
property output_quantizers
Get the input quantizers.
Returns:
List[QuantizedArray]: the input quantizers
property quantize_input
Get the input quantization function.
Returns:
Callable : function that quantizes the input
method fit
Fit the FHE linear model.
Args:
X : training data By default, you should be able to pass: * numpy arrays * torch tensors * pandas DataFrame or Series
y (numpy.ndarray): The target data.
Returns: Any
class ElasticNet
An ElasticNet regression model with FHE.
Arguments:
n_bits (int): default is 2.
For more details on ElasticNet please refer to the scikit-learn documentation: https://scikit-learn.org/stable/modules/generated/sklearn.linear_model.ElasticNet.html
method __init__
property fhe_circuit
Get the FHE circuit.
Returns:
Circuit: the FHE circuit
property input_quantizers
Get the input quantizers.
Returns:
List[QuantizedArray]: the input quantizers
property onnx_model
Get the ONNX model.
.. # noqa: DAR201
Returns:
onnx.ModelProto: the ONNX model
property output_quantizers
Get the input quantizers.
Returns:
List[QuantizedArray]: the input quantizers
property quantize_input
Get the input quantization function.
Returns:
Callable : function that quantizes the input
class Lasso
A Lasso regression model with FHE.
Arguments:
n_bits (int): default is 2.
For more details on Lasso please refer to the scikit-learn documentation: https://scikit-learn.org/stable/modules/generated/sklearn.linear_model.Lasso.html
method __init__
property fhe_circuit
Get the FHE circuit.
Returns:
Circuit: the FHE circuit
property input_quantizers
Get the input quantizers.
Returns:
List[QuantizedArray]: the input quantizers
property onnx_model
Get the ONNX model.
.. # noqa: DAR201
Returns:
onnx.ModelProto: the ONNX model
property output_quantizers
Get the input quantizers.
Returns:
List[QuantizedArray]: the input quantizers
property quantize_input
Get the input quantization function.
Returns:
Callable : function that quantizes the input
class Ridge
A Ridge regression model with FHE.
Arguments:
n_bits (int): default is 2.
For more details on Ridge please refer to the scikit-learn documentation: https://scikit-learn.org/stable/modules/generated/sklearn.linear_model.Ridge.html
method __init__
property fhe_circuit
Get the FHE circuit.
Returns:
Circuit: the FHE circuit
property input_quantizers
Get the input quantizers.
Returns:
List[QuantizedArray]: the input quantizers
property onnx_model
Get the ONNX model.
.. # noqa: DAR201
Returns:
onnx.ModelProto: the ONNX model
property output_quantizers
Get the input quantizers.
Returns:
List[QuantizedArray]: the input quantizers
property quantize_input
Get the input quantization function.
Returns:
Callable : function that quantizes the input
class LogisticRegression
A logistic regression model with FHE.
Arguments:
n_bits (int): default is 2.
For more details on LogisticRegression please refer to the scikit-learn documentation: https://scikit-learn.org/stable/modules/generated/sklearn.linear_model.LogisticRegression.html
feature is experimental and should be used carefully. Important note
: it only works for a LinearRegression model with N features, N a power of 2, for now. More information available in the QuantizedReduceSum operator. Default to False.
*args
: The arguments to pass to the sklearn linear model.
**kwargs: The keyword arguments to pass to the sklearn linear model.
Fill a parameter set structure from kwargs parameters.
Args:
obj: an object of type klass, if None the object is created if any of the type's members appear in the kwargs
klass: the type of object to fill
Returns:
obj: an object of type klass
kwargs: remaining parameter names and values that were not filled into obj
Raises:
TypeError: if the types of the parameters in kwargs could not be converted to the corresponding types of members of klass
class QuantizationOptions
Options for quantization.
Determines the number of bits for quantization and the method of quantization of the values. Signed quantization allows negative quantized values. Symmetric quantization assumes the float values are distributed symmetrically around x=0 and assigns signed values around 0 to the float values. QAT (quantization aware training) quantization assumes the values are already quantized, taking a discrete set of values, and assigns these values to integers, computing only the scale.
method __init__
property quant_options
Get a copy of the quantization parameters.
Returns:
UniformQuantizationParameters: a copy of the current quantization parameters
method copy_opts
Copy the options from a different structure.
Args:
opts (QuantizationOptions): structure to copy parameters from.
class MinMaxQuantizationStats
Calibration set statistics.
This class stores the statistics for the calibration set or for a calibration data batch. Currently we only store min/max to determine the quantization range. The min/max are computed from the calibration set.
property quant_stats
Get a copy of the calibration set statistics.
Returns:
MinMaxQuantizationStats: a copy of the current quantization stats
method check_is_uniform_quantized
Check if these statistics correspond to uniformly quantized values.
Determines whether the values represented by this QuantizedArray show a quantized structure that allows to infer the scale of quantization.
Args:
options (QuantizationOptions): used to quantize the values in the QuantizedArray
Returns:
bool: check result.
method compute_quantization_stats
Compute the calibration set quantization statistics.
Args:
values (numpy.ndarray): Calibration set on which to compute statistics.
method copy_stats
Copy the statistics from a different structure.
Args:
stats (MinMaxQuantizationStats): structure to copy statistics from.
class UniformQuantizationParameters
Quantization parameters for uniform quantization.
This class stores the parameters used for quantizing real values to discrete integer values. The parameters are computed from quantization options and quantization statistics.
property quant_params
Get a copy of the quantization parameters.
Returns:
UniformQuantizationParameters: a copy of the current quantization parameters
method compute_quantization_parameters
Compute the quantization parameters.
Args:
options (QuantizationOptions): quantization options set
stats (MinMaxQuantizationStats): calibrated statistics for quantization
method copy_params
Copy the parameters from a different structure.
Args:
params (UniformQuantizationParameters): parameter structure to copy
class UniformQuantizer
Uniform quantizer.
Contains all information necessary for uniform quantization and provides quantization/dequantization functionality on numpy arrays.
Args:
options (QuantizationOptions): Quantization options set
stats (Optional[MinMaxQuantizationStats]): Quantization batch statistics set
method __init__
property quant_options
Get a copy of the quantization parameters.
Returns:
UniformQuantizationParameters: a copy of the current quantization parameters
property quant_params
Get a copy of the quantization parameters.
Returns:
UniformQuantizationParameters: a copy of the current quantization parameters
property quant_stats
Get a copy of the calibration set statistics.
Returns:
MinMaxQuantizationStats: a copy of the current quantization stats
method check_is_uniform_quantized
Check if these statistics correspond to uniformly quantized values.
Determines whether the values represented by this QuantizedArray show a quantized structure that allows to infer the scale of quantization.
Args:
options (QuantizationOptions): used to quantize the values in the QuantizedArray
Returns:
bool: check result.
method compute_quantization_parameters
Compute the quantization parameters.
Args:
options (QuantizationOptions): quantization options set
stats (MinMaxQuantizationStats): calibrated statistics for quantization
method compute_quantization_stats
Compute the calibration set quantization statistics.
Args:
values (numpy.ndarray): Calibration set on which to compute statistics.
method copy_opts
Copy the options from a different structure.
Args:
opts (QuantizationOptions): structure to copy parameters from.
method copy_params
Copy the parameters from a different structure.
Args:
params (UniformQuantizationParameters): parameter structure to copy
method copy_stats
Copy the statistics from a different structure.
Args:
stats (MinMaxQuantizationStats): structure to copy statistics from.
method dequant
Dequantize values.
Args:
qvalues (numpy.ndarray): integer values to dequantize
Returns:
numpy.ndarray: Dequantized float values.
method quant
Quantize values.
Args:
values (numpy.ndarray): float values to quantize
Returns:
numpy.ndarray: Integer quantized values.
class QuantizedArray
Abstraction of quantized array.
Contains float values and their quantized integer counter-parts. Quantization is performed by the quantizer member object. Float and int values are kept in sync. Having both types of values is useful since quantized operators in Concrete ML graphs might need one or the other depending on how the operator works (in float or in int). Moreover, when the encrypted function needs to return a value, it must return integer values.
See https://arxiv.org/abs/1712.05877.
Args:
values (numpy.ndarray): Values to be quantized.
n_bits (int): The number of bits to use for quantization.
method __init__
method dequant
Dequantize self.qvalues.
Returns:
numpy.ndarray: Dequantized values.
method quant
Quantize self.values.
Returns:
numpy.ndarray: Quantized values.
method update_quantized_values
Update qvalues to get their corresponding values using the related quantized parameters.
Args:
qvalues (numpy.ndarray): Values to replace self.qvalues
Returns:
values (numpy.ndarray): Corresponding values
method update_values
Update values to get their corresponding qvalues using the related quantized parameters.
Args:
values (numpy.ndarray): Values to replace self.values
Returns:
qvalues (numpy.ndarray): Corresponding qvalues
kwargs
: parameter names and values to fill into an instance of the klass type
params
(Optional[UniformQuantizationParameters]): Quantization parameters set (scale, zero-point)
value_is_float
(bool, optional): Whether the passed values are real (float) values or not. If False, the values will be quantized according to the passed scale and zero_point. Defaults to True.
options (QuantizationOptions): Quantization options set
stats (Optional[MinMaxQuantizationStats]): Quantization batch statistics set
params (Optional[UniformQuantizationParameters]): Quantization parameters set (scale, zero-point)
kwargs: Any member of the options, stats, params sets as a key-value pair. The parameter sets need to be completely parametrized if their members appear in kwargs.
Protocols are used to mix type hinting with duck-typing. Indeed we don't always want to have an abstract parent class between all objects. We are more interested in the behavior of such objects. Implementing a Protocol is a way to specify the behavior of objects.
To read more about Protocol please read: https://peps.python.org/pep-0544
class Quantizer
Quantizer Protocol.
To use to type hint a quantizer.
method dequant
Dequantize some values.
Args:
X (numpy.ndarray): Values to dequantize
.. # noqa: DAR202
Returns:
numpy.ndarray: Dequantized values
method quant
Quantize some values.
Args:
values (numpy.ndarray): Values to quantize
.. # noqa: DAR202
Returns:
numpy.ndarray: The quantized values
class ConcreteBaseEstimatorProtocol
A Concrete Estimator Protocol.
property onnx_model
onnx_model.
.. # noqa: DAR202
Results: onnx.ModelProto
property quantize_input
Quantize input function.
method compile
Compiles a model to a FHE Circuit.
Args:
X (numpy.ndarray): the dequantized dataset
configuration (Optional[Configuration]): the options for compilation
.. # noqa: DAR202
Returns:
Circuit: the compiled Circuit.
method fit
Initialize and fit the module.
Args:
X : training data By default, you should be able to pass: * numpy arrays * torch tensors * pandas DataFrame or Series
y (numpy.ndarray): labels associated with training data
.. # noqa: DAR202
Returns:
ConcreteBaseEstimatorProtocol: the trained estimator
method fit_benchmark
Fit the quantized estimator and return reference estimator.
This function returns both the quantized estimator (itself), but also a wrapper around the non-quantized trained NN. This is useful in order to compare performance between the quantized and fp32 versions of the classifier
Args:
X : training data By default, you should be able to pass: * numpy arrays * torch tensors * pandas DataFrame or Series
y (numpy.ndarray): labels associated with training data
.. # noqa: DAR202
Returns:
self: self fitted
model: underlying estimator
method post_processing
Post-process models predictions.
Args:
y_preds (numpy.ndarray): predicted values by model (clear-quantized)
.. # noqa: DAR202
Returns:
numpy.ndarray: the post-processed predictions
class ConcreteBaseClassifierProtocol
Concrete classifier protocol.
property onnx_model
onnx_model.
.. # noqa: DAR202
Results: onnx.ModelProto
property quantize_input
Quantize input function.
method compile
Compiles a model to a FHE Circuit.
Args:
X (numpy.ndarray): the dequantized dataset
configuration (Optional[Configuration]): the options for compilation
.. # noqa: DAR202
Returns:
Circuit: the compiled Circuit.
method fit
Initialize and fit the module.
Args:
X : training data By default, you should be able to pass: * numpy arrays * torch tensors * pandas DataFrame or Series
y (numpy.ndarray): labels associated with training data
.. # noqa: DAR202
Returns:
ConcreteBaseEstimatorProtocol: the trained estimator
method fit_benchmark
Fit the quantized estimator and return reference estimator.
This function returns both the quantized estimator (itself), but also a wrapper around the non-quantized trained NN. This is useful in order to compare performance between the quantized and fp32 versions of the classifier
Args:
X : training data By default, you should be able to pass: * numpy arrays * torch tensors * pandas DataFrame or Series
y (numpy.ndarray): labels associated with training data
.. # noqa: DAR202
Returns:
self: self fitted
model: underlying estimator
method post_processing
Post-process models predictions.
Args:
y_preds (numpy.ndarray): predicted values by model (clear-quantized)
.. # noqa: DAR202
Returns:
numpy.ndarray: the post-processed predictions
method predict
Predicts for each sample the class with highest probability.
Args:
X (numpy.ndarray): Features
execute_in_fhe (bool): Whether the inference should be done in fhe or not.
.. # noqa: DAR202
Returns: numpy.ndarray
method predict_proba
Predicts for each sample the probability of each class.
Args:
X (numpy.ndarray): Features
execute_in_fhe (bool): Whether the inference should be done in fhe or not.
.. # noqa: DAR202
Returns: numpy.ndarray
class ConcreteBaseRegressorProtocol
Concrete regressor protocol.
property onnx_model
onnx_model.
.. # noqa: DAR202
Results: onnx.ModelProto
property quantize_input
Quantize input function.
method compile
Compiles a model to a FHE Circuit.
Args:
X (numpy.ndarray): the dequantized dataset
configuration (Optional[Configuration]): the options for compilation
.. # noqa: DAR202
Returns:
Circuit: the compiled Circuit.
method fit
Initialize and fit the module.
Args:
X : training data By default, you should be able to pass: * numpy arrays * torch tensors * pandas DataFrame or Series
y (numpy.ndarray): labels associated with training data
.. # noqa: DAR202
Returns:
ConcreteBaseEstimatorProtocol: the trained estimator
method fit_benchmark
Fit the quantized estimator and return reference estimator.
This function returns both the quantized estimator (itself), but also a wrapper around the non-quantized trained NN. This is useful in order to compare performance between the quantized and fp32 versions of the classifier
Args:
X : training data By default, you should be able to pass: * numpy arrays * torch tensors * pandas DataFrame or Series
y (numpy.ndarray): labels associated with training data
.. # noqa: DAR202
Returns:
self: self fitted
model: underlying estimator
method post_processing
Post-process models predictions.
Args:
y_preds (numpy.ndarray): predicted values by model (clear-quantized)
.. # noqa: DAR202
Returns:
numpy.ndarray: the post-processed predictions
method predict
Predicts for each sample the expected value.
Args:
X (numpy.ndarray): Features
execute_in_fhe (bool): Whether the inference should be done in fhe or not.
.. # noqa: DAR202
Returns: numpy.ndarray
compilation_artifacts
(Optional[DebugArtifacts]): artifacts object to fill during compilation
show_mlir (bool): whether or not to show MLIR during the compilation
use_virtual_lib (bool): whether to compile using the virtual library that allows higher bitwidths
p_error (float): probability of error of a PBS
**fit_params
: additional parameters that can be used during training
*args
: The arguments to pass to the underlying model.
**kwargs: The keyword arguments to pass to the underlying model.
compilation_artifacts
(Optional[DebugArtifacts]): artifacts object to fill during compilation
show_mlir (bool): whether or not to show MLIR during the compilation
use_virtual_lib (bool): whether to compile using the virtual library that allows higher bitwidths
p_error (float): probability of error of a PBS
**fit_params
: additional parameters that can be used during training
*args
: The arguments to pass to the underlying model.
**kwargs: The keyword arguments to pass to the underlying model.
compilation_artifacts
(Optional[DebugArtifacts]): artifacts object to fill during compilation
show_mlir (bool): whether or not to show MLIR during the compilation
use_virtual_lib (bool): whether to compile using the virtual library that allows higher bitwidths
p_error (float): probability of error of a PBS
**fit_params
: additional parameters that can be used during training
*args
: The arguments to pass to the underlying model.
**kwargs: The keyword arguments to pass to the underlying model.
Scikit-learn interface for concrete quantized neural networks.
Global Variables
MAXIMUM_TLU_BIT_WIDTH
class SparseQuantNeuralNetImpl
Sparse Quantized Neural Network classifier.
This class implements an MLP that is compatible with FHE constraints. The weights and activations are quantized to low bitwidth and pruning is used to ensure accumulators do not surpass an user-provided accumulator bit-width. The number of classes and number of layers are specified by the user, as well as the breadth of the network
method __init__
Sparse Quantized Neural Network constructor.
Args:
input_dim: Number of dimensions of the input data
n_layers: Number of linear layers for this network
Raises:
ValueError: if the parameters have invalid values or the computed accumulator bitwidth is zero
method enable_pruning
Enable pruning in the network. Pruning must be made permanent to recover pruned weights.
Raises:
ValueError: if the quantization parameters are invalid
method forward
Forward pass.
Args:
x (torch.Tensor): network input
Returns:
x (torch.Tensor): network prediction
method make_pruning_permanent
Make the learned pruning permanent in the network.
method max_active_neurons
Compute the maximum number of active (non-zero weight) neurons.
The computation is done using the quantization parameters passed to the constructor. Warning: With the current quantization algorithm (asymmetric) the value returned by this function is not guaranteed to ensure FHE compatibility. For some weight distributions, weights that are 0 (which are pruned weights) will not be quantized to 0. Therefore the total number of active quantized neurons will not be equal to max_active_neurons.
Returns:
n (int): maximum number of active neurons
method on_train_end
Call back when training is finished, can be useful to remove training hooks.
class QuantizedSkorchEstimatorMixin
Mixin class that adds quantization features to Skorch NN estimators.
property base_estimator_type
Get the sklearn estimator that should be trained by the child class.
property base_module_to_compile
Get the module that should be compiled to FHE. In our case this is a torch nn.Module.
Returns:
module (nn.Module): the instantiated torch module
property fhe_circuit
Get the FHE circuit.
Returns:
Circuit: the FHE circuit
property input_quantizers
Get the input quantizers.
Returns:
List[Quantizer]: the input quantizers
property n_bits_quant
Return the number of quantization bits.
This is stored by the torch.nn.module instance and thus cannot be retrieved until this instance is created.
Returns:
n_bits (int): the number of bits to quantize the network
Raises:
ValueError: with skorch estimators, the module_ is not instantiated until .fit() is called. Thus this estimator needs to be .fit() before we get the quantization number of bits. If it is not trained we raise an exception
property onnx_model
Get the ONNX model.
.. # noqa: DAR201
Returns:
_onnx_model_ (onnx.ModelProto): the ONNX model
property output_quantizers
Get the input quantizers.
Returns:
List[QuantizedArray]: the input quantizers
property quantize_input
Get the input quantization function.
Returns:
Callable : function that quantizes the input
method get_params_for_benchmark
Get parameters for benchmark when cloning a skorch wrapped NN.
We must remove all parameters related to the module. Skorch takes either a class or a class instance for the module parameter. We want to pass our trained model, a class instance. But for this to work, we need to remove all module related constructor params. If not, skorch will instantiate a new class instance of the same type as the passed module see skorch net.py NeuralNet::initialize_instance
Returns:
params (dict): parameters to create an equivalent fp32 sklearn estimator for benchmark
method infer
Perform a single inference step on a batch of data.
This method is specific to Skorch estimators.
Args:
x (torch.Tensor): A batch of the input data, produced by a Dataset
**fit_params (dict) : Additional parameters passed to the forward method of the module and to the self.train_split call.
Returns: A torch tensor with the inference results for each item in the input
method on_train_end
Call back when training is finished by the skorch wrapper.
Check if the underlying neural net has a callback for this event and, if so, call it.
Args:
net: estimator for which training has ended (equal to self)
X: data
class FixedTypeSkorchNeuralNet
A mixin with a helpful modification to a skorch estimator that fixes the module type.
method get_params
Get parameters for this estimator.
Args:
deep (bool): If True, will return the parameters for this estimator and contained subobjects that are estimators.
**kwargs: any additional parameters to pass to the sklearn BaseEstimator class
Returns:
params : dict, Parameter names mapped to their values.
class NeuralNetClassifier
Scikit-learn interface for quantized FHE compatible neural networks.
This class wraps a quantized NN implemented using our Torch tools as a scikit-learn Estimator. It uses the skorch package to handle training and scikit-learn compatibility, and adds quantization and compilation functionality. The neural network implemented by this class is a multi layer fully connected network trained with Quantization Aware Training (QAT).
The datatypes that are allowed for prediction by this wrapper are more restricted than standard scikit-learn estimators as this class needs to predict in FHE and network inference executor is the NumpyModule.
method __init__
property base_estimator_type
property base_module_to_compile
Get the module that should be compiled to FHE. In our case this is a torch nn.Module.
Returns:
module (nn.Module): the instantiated torch module
property classes_
property fhe_circuit
Get the FHE circuit.
Returns:
Circuit: the FHE circuit
property history
property input_quantizers
Get the input quantizers.
Returns:
List[Quantizer]: the input quantizers
property n_bits_quant
Return the number of quantization bits.
This is stored by the torch.nn.module instance and thus cannot be retrieved until this instance is created.
Returns:
n_bits (int): the number of bits to quantize the network
Raises:
ValueError: with skorch estimators, the module_ is not instantiated until .fit() is called. Thus this estimator needs to be .fit() before we get the quantization number of bits. If it is not trained we raise an exception
property onnx_model
Get the ONNX model.
.. # noqa: DAR201
Returns:
_onnx_model_ (onnx.ModelProto): the ONNX model
property output_quantizers
Get the input quantizers.
Returns:
List[QuantizedArray]: the input quantizers
property quantize_input
Get the input quantization function.
Returns:
Callable : function that quantizes the input
method fit
method get_params
Get parameters for this estimator.
Args:
deep (bool): If True, will return the parameters for this estimator and contained subobjects that are estimators.
**kwargs: any additional parameters to pass to the sklearn BaseEstimator class
Returns:
params : dict, Parameter names mapped to their values.
method get_params_for_benchmark
Get parameters for benchmark when cloning a skorch wrapped NN.
We must remove all parameters related to the module. Skorch takes either a class or a class instance for the module parameter. We want to pass our trained model, a class instance. But for this to work, we need to remove all module related constructor params. If not, skorch will instantiate a new class instance of the same type as the passed module see skorch net.py NeuralNet::initialize_instance
Returns:
params (dict): parameters to create an equivalent fp32 sklearn estimator for benchmark
method infer
Perform a single inference step on a batch of data.
This method is specific to Skorch estimators.
Args:
x (torch.Tensor): A batch of the input data, produced by a Dataset
**fit_params (dict) : Additional parameters passed to the forward method of the module and to the self.train_split call.
Returns: A torch tensor with the inference results for each item in the input
method on_train_end
Call back when training is finished by the skorch wrapper.
Check if the underlying neural net has a callback for this event and, if so, call it.
Args:
net: estimator for which training has ended (equal to self)
X: data
method predict
Predict on user provided data.
Predicts using the quantized clear or FHE classifier
Args:
X : input data, a numpy array of raw values (non quantized)
execute_in_fhe : whether to execute the inference in FHE or in the clear
Returns:
y_pred : numpy ndarray with predictions
class NeuralNetRegressor
Scikit-learn interface for quantized FHE compatible neural networks.
This class wraps a quantized NN implemented using our Torch tools as a scikit-learn Estimator. It uses the skorch package to handle training and scikit-learn compatibility, and adds quantization and compilation functionality. The neural network implemented by this class is a multi layer fully connected network trained with Quantization Aware Training (QAT).
The datatypes that are allowed for prediction by this wrapper are more restricted than standard scikit-learn estimators as this class needs to predict in FHE and network inference executor is the NumpyModule.
method __init__
property base_estimator_type
property base_module_to_compile
Get the module that should be compiled to FHE. In our case this is a torch nn.Module.
Returns:
module (nn.Module): the instantiated torch module
property fhe_circuit
Get the FHE circuit.
Returns:
Circuit: the FHE circuit
property history
property input_quantizers
Get the input quantizers.
Returns:
List[Quantizer]: the input quantizers
property n_bits_quant
Return the number of quantization bits.
This is stored by the torch.nn.module instance and thus cannot be retrieved until this instance is created.
Returns:
n_bits (int): the number of bits to quantize the network
Raises:
ValueError: with skorch estimators, the module_ is not instantiated until .fit() is called. Thus this estimator needs to be .fit() before we get the quantization number of bits. If it is not trained we raise an exception
property onnx_model
Get the ONNX model.
.. # noqa: DAR201
Returns:
_onnx_model_ (onnx.ModelProto): the ONNX model
property output_quantizers
Get the input quantizers.
Returns:
List[QuantizedArray]: the input quantizers
property quantize_input
Get the input quantization function.
Returns:
Callable : function that quantizes the input
method fit
method get_params
Get parameters for this estimator.
Args:
deep (bool): If True, will return the parameters for this estimator and contained subobjects that are estimators.
**kwargs: any additional parameters to pass to the sklearn BaseEstimator class
Returns:
params : dict, Parameter names mapped to their values.
method get_params_for_benchmark
Get parameters for benchmark when cloning a skorch wrapped NN.
We must remove all parameters related to the module. Skorch takes either a class or a class instance for the module parameter. We want to pass our trained model, a class instance. But for this to work, we need to remove all module related constructor params. If not, skorch will instantiate a new class instance of the same type as the passed module see skorch net.py NeuralNet::initialize_instance
Returns:
params (dict): parameters to create an equivalent fp32 sklearn estimator for benchmark
method infer
Perform a single inference step on a batch of data.
This method is specific to Skorch estimators.
Args:
x (torch.Tensor): A batch of the input data, produced by a Dataset
**fit_params (dict) : Additional parameters passed to the forward method of the module and to the self.train_split call.
Returns: A torch tensor with the inference results for each item in the input
method on_train_end
Call back when training is finished by the skorch wrapper.
Check if the underlying neural net has a callback for this event and, if so, call it.
Args:
net: estimator for which training has ended (equal to self)
X: data
n_outputs
: Number of output classes or regression targets
n_w_bits: Number of weight bits
n_a_bits: Number of activation and input bits
n_accum_bits: Maximal allowed bitwidth of intermediate accumulators
n_hidden_neurons_multiplier: A factor that is multiplied by the maximal number of active (non-zero weight) neurons for every layer. The maximal number of neurons in the worst case scenario is: 2^n_max-1 max_active_neurons(n_max, n_w, n_a) = floor(---------------------) (2^n_w-1)*(2^n_a-1) ) The worst case scenario for the bitwidth of the accumulator is when all weights and activations are maximum simultaneously. We set, for each layer, the total number of neurons to be: n_hidden_neurons_multiplier * max_active_neurons(n_accum_bits, n_w_bits, n_a_bits) Through experiments, for typical distributions of weights and activations, the default value for n_hidden_neurons_multiplier, 4, is safe to avoid overflow.
activation_function: a torch class that is used to construct activation functions in the network (e.g. torch.ReLU, torch.SELU, torch.Sigmoid, etc)
Module that contains base classes for our libraries estimators.
Global Variables
DEFAULT_P_ERROR_PBS
OPSET_VERSION_FOR_ONNX_EXPORT
class QuantizedTorchEstimatorMixin
Mixin that provides quantization for a torch module and follows the Estimator API.
This class should be mixed in with another that provides the full Estimator API. This class only provides modifiers for .fit() (with quantization) and .predict() (optionally in FHE)
method __init__
property base_estimator_type
Get the sklearn estimator that should be trained by the child class.
property base_module_to_compile
Get the Torch module that should be compiled to FHE.
property fhe_circuit
Get the FHE circuit.
Returns:
Circuit: the FHE circuit
property input_quantizers
Get the input quantizers.
Returns:
List[Quantizer]: the input quantizers
property n_bits_quant
Get the number of quantization bits.
property onnx_model
Get the ONNX model.
.. # noqa: DAR201
Returns:
_onnx_model_ (onnx.ModelProto): the ONNX model
property output_quantizers
Get the input quantizers.
Returns:
List[QuantizedArray]: the input quantizers
property quantize_input
Get the input quantization function.
Returns:
Callable : function that quantizes the input
method compile
Compile the model.
Args:
X (numpy.ndarray): the dequantized dataset
configuration (Optional[Configuration]): the options for compilation
Returns:
Circuit: the compiled Circuit.
Raises:
ValueError: if called before the model is trained
method fit
Initialize and fit the module.
If the module was already initialized, by calling fit, the module will be re-initialized (unless warm_start is True). In addition to the torch training step, this method performs quantization of the trained torch model.
Args:
X : training data By default, you should be able to pass: * numpy arrays * torch tensors * pandas DataFrame or Series
y (numpy.ndarray): labels associated with training data
Returns:
self: the trained quantized estimator
method fit_benchmark
Fit the quantized estimator and return reference estimator.
This function returns both the quantized estimator (itself), but also a wrapper around the non-quantized trained NN. This is useful in order to compare performance between the quantized and fp32 versions of the classifier
Args:
X : training data By default, you should be able to pass: * numpy arrays * torch tensors * pandas DataFrame or Series
y (numpy.ndarray): labels associated with training data
Returns:
self: the trained quantized estimator
fp32_model: trained raw (fp32) wrapped NN estimator
method get_params_for_benchmark
Get the parameters to instantiate the sklearn estimator trained by the child class.
Returns:
params (dict): dictionary with parameters that will initialize a new Estimator
method post_processing
Post-processing the output.
Args:
y_preds (numpy.ndarray): the output to post-process
Raises:
ValueError: if unknown post-processing function
Returns:
numpy.ndarray: the post-processed output
method predict
Predict on user provided data.
Predicts using the quantized clear or FHE classifier
Args:
X : input data, a numpy array of raw values (non quantized)
execute_in_fhe : whether to execute the inference in FHE or in the clear
Returns:
y_pred : numpy ndarray with predictions
method predict_proba
Predict on user provided data, returning probabilities.
Predicts using the quantized clear or FHE classifier
Args:
X : input data, a numpy array of raw values (non quantized)
execute_in_fhe : whether to execute the inference in FHE or in the clear
Returns:
y_pred : numpy ndarray with probabilities (if applicable)
Raises:
ValueError: if the estimator was not yet trained or compiled
class BaseTreeEstimatorMixin
Mixin class for tree-based estimators.
A place to share methods that are used on all tree-based estimators.
method __init__
Initialize the TreeBasedEstimatorMixin.
Args:
n_bits (int): number of bits used for quantization
property onnx_model
Get the ONNX model.
.. # noqa: DAR201
Returns:
onnx.ModelProto: the ONNX model
method compile
Compile the model.
Args:
X (numpy.ndarray): the dequantized dataset
configuration (Optional[Configuration]): the options for compilation
Returns:
Circuit: the compiled Circuit.
method dequantize_output
Dequantize the integer predictions.
Args:
y_preds (numpy.ndarray): the predictions
Returns: the dequantized predictions
method fit_benchmark
Fit the sklearn tree-based model and the FHE tree-based model.
Args:
X (numpy.ndarray): The input data.
y (numpy.ndarray): The target data. random_state (Optional[Union[int, numpy.random.RandomState, None]]): The random state. Defaults to None.
Returns: Tuple[ConcreteEstimators, SklearnEstimators]: The FHE and sklearn tree-based models.
method quantize_input
Quantize the input.
Args:
X (numpy.ndarray): the input
Returns: the quantized input
class BaseTreeRegressorMixin
Mixin class for tree-based regressors.
A place to share methods that are used on all tree-based regressors.
method __init__
Initialize the TreeBasedEstimatorMixin.
Args:
n_bits (int): number of bits used for quantization
property onnx_model
Get the ONNX model.
.. # noqa: DAR201
Returns:
onnx.ModelProto: the ONNX model
method compile
Compile the model.
Args:
X (numpy.ndarray): the dequantized dataset
configuration (Optional[Configuration]): the options for compilation
Returns:
Circuit: the compiled Circuit.
method dequantize_output
Dequantize the integer predictions.
Args:
y_preds (numpy.ndarray): the predictions
Returns: the dequantized predictions
method fit
Fit the tree-based estimator.
Args:
X : training data By default, you should be able to pass: * numpy arrays * torch tensors * pandas DataFrame or Series
y (numpy.ndarray): The target data.
Returns:
Any: The fitted model.
method fit_benchmark
Fit the sklearn tree-based model and the FHE tree-based model.
Args:
X (numpy.ndarray): The input data.
y (numpy.ndarray): The target data. random_state (Optional[Union[int, numpy.random.RandomState, None]]): The random state. Defaults to None.
Returns: Tuple[ConcreteEstimators, SklearnEstimators]: The FHE and sklearn tree-based models.
method post_processing
Apply post-processing to the predictions.
Args:
y_preds (numpy.ndarray): The predictions.
Returns:
numpy.ndarray: The post-processed predictions.
method predict
Predict the probability.
Args:
X (numpy.ndarray): The input data.
execute_in_fhe (bool): Whether to execute in FHE. Defaults to False.
Returns:
numpy.ndarray: The predicted probabilities.
method quantize_input
Quantize the input.
Args:
X (numpy.ndarray): the input
Returns: the quantized input
class BaseTreeClassifierMixin
Mixin class for tree-based classifiers.
A place to share methods that are used on all tree-based classifiers.
method __init__
Initialize the TreeBasedEstimatorMixin.
Args:
n_bits (int): number of bits used for quantization
property onnx_model
Get the ONNX model.
.. # noqa: DAR201
Returns:
onnx.ModelProto: the ONNX model
method compile
Compile the model.
Args:
X (numpy.ndarray): the dequantized dataset
configuration (Optional[Configuration]): the options for compilation
Returns:
Circuit: the compiled Circuit.
method dequantize_output
Dequantize the integer predictions.
Args:
y_preds (numpy.ndarray): the predictions
Returns: the dequantized predictions
method fit
Fit the tree-based estimator.
Args:
X : training data By default, you should be able to pass: * numpy arrays * torch tensors * pandas DataFrame or Series
y (numpy.ndarray): The target data.
Returns:
Any: The fitted model.
method fit_benchmark
Fit the sklearn tree-based model and the FHE tree-based model.
Args:
X (numpy.ndarray): The input data.
y (numpy.ndarray): The target data. random_state (Optional[Union[int, numpy.random.RandomState, None]]): The random state. Defaults to None.
Returns: Tuple[ConcreteEstimators, SklearnEstimators]: The FHE and sklearn tree-based models.
method post_processing
Apply post-processing to the predictions.
Args:
y_preds (numpy.ndarray): The predictions.
Returns:
numpy.ndarray: The post-processed predictions.
method predict
Predict the class with highest probability.
Args:
X (numpy.ndarray): The input data.
execute_in_fhe (bool): Whether to execute in FHE. Defaults to False.
Returns:
numpy.ndarray: The predicted target values.
method predict_proba
Predict the probability.
Args:
X (numpy.ndarray): The input data.
execute_in_fhe (bool): Whether to execute in FHE. Defaults to False.
Returns:
numpy.ndarray: The predicted probabilities.
method quantize_input
Quantize the input.
Args:
X (numpy.ndarray): the input
Returns: the quantized input
class SklearnLinearModelMixin
A Mixin class for sklearn linear models with FHE.
method __init__
Initialize the FHE linear model.
Args:
n_bits (int, Dict): Number of bits to quantize the model. If an int is passed for n_bits, the value will be used for activation, inputs and weights. If a dict is passed, then it should contain "model_inputs", "op_inputs", "op_weights" and "model_outputs" keys with corresponding number of quantization bits for: - model_inputs : number of bits for model input - op_inputs : number of bits to quantize layer input values - op_weights: learned parameters or constants in the network - model_outputs: final model output quantization bits Default to 2.
*args: The arguments to pass to the sklearn linear model.
property fhe_circuit
Get the FHE circuit.
Returns:
Circuit: the FHE circuit
property input_quantizers
Get the input quantizers.
Returns:
List[QuantizedArray]: the input quantizers
property onnx_model
Get the ONNX model.
.. # noqa: DAR201
Returns:
onnx.ModelProto: the ONNX model
property output_quantizers
Get the input quantizers.
Returns:
List[QuantizedArray]: the input quantizers
property quantize_input
Get the input quantization function.
Returns:
Callable : function that quantizes the input
method clean_graph
Clean the graph of the onnx model.
This will remove the Cast node in the model's onnx.graph since they have no use in quantized or FHE models.
method compile
Compile the FHE linear model.
Args:
X (numpy.ndarray): The input data.
configuration (Optional[Configuration]): Configuration object to use during compilation
Returns:
Circuit: the compiled Circuit.
method fit
Fit the FHE linear model.
Args:
X : training data By default, you should be able to pass: * numpy arrays * torch tensors * pandas DataFrame or Series
y (numpy.ndarray): The target data.
Returns: Any
method fit_benchmark
Fit the sklearn linear model and the FHE linear model.
Args:
X (numpy.ndarray): The input data.
y (numpy.ndarray): The target data. random_state (Optional[Union[int, numpy.random.RandomState, None]]): The random state. Defaults to None.
Returns: Tuple[SklearnLinearModelMixin, sklearn.linear_model.LinearRegression]: The FHE and sklearn LinearRegression.
method post_processing
Post-processing the output.
Args:
y_preds (numpy.ndarray): the output to post-process
Returns:
numpy.ndarray: the post-processed output
method predict
Predict on user data.
Predict on user data using either the quantized clear model, implemented with tensors, or, if execute_in_fhe is set, using the compiled FHE circuit
Args:
X (numpy.ndarray): the input data
execute_in_fhe (bool): whether to execute the inference in FHE
Returns:
numpy.ndarray: the prediction as ordinals
class SklearnLinearClassifierMixin
A Mixin class for sklearn linear classifiers with FHE.
method __init__
Initialize the FHE linear model.
Args:
n_bits (int, Dict): Number of bits to quantize the model. If an int is passed for n_bits, the value will be used for activation, inputs and weights. If a dict is passed, then it should contain "model_inputs", "op_inputs", "op_weights" and "model_outputs" keys with corresponding number of quantization bits for: - model_inputs : number of bits for model input - op_inputs : number of bits to quantize layer input values - op_weights: learned parameters or constants in the network - model_outputs: final model output quantization bits Default to 2.
*args: The arguments to pass to the sklearn linear model.
property fhe_circuit
Get the FHE circuit.
Returns:
Circuit: the FHE circuit
property input_quantizers
Get the input quantizers.
Returns:
List[QuantizedArray]: the input quantizers
property onnx_model
Get the ONNX model.
.. # noqa: DAR201
Returns:
onnx.ModelProto: the ONNX model
property output_quantizers
Get the input quantizers.
Returns:
List[QuantizedArray]: the input quantizers
property quantize_input
Get the input quantization function.
Returns:
Callable : function that quantizes the input
method clean_graph
Clean the graph of the onnx model.
Any operators following gemm, including the sigmoid, softmax and argmax operators, are removed from the graph. They will be executed in clear in the post-processing method.
method compile
Compile the FHE linear model.
Args:
X (numpy.ndarray): The input data.
configuration (Optional[Configuration]): Configuration object to use during compilation
Returns:
Circuit: the compiled Circuit.
method decision_function
Predict confidence scores for samples.
Args:
X (numpy.ndarray): Samples to predict.
execute_in_fhe (bool): If True, the inference will be executed in FHE. Default to False.
Returns:
numpy.ndarray: Confidence scores for samples.
method fit
Fit the FHE linear model.
Args:
X : training data By default, you should be able to pass: * numpy arrays * torch tensors * pandas DataFrame or Series
y (numpy.ndarray): The target data.
Returns: Any
method fit_benchmark
Fit the sklearn linear model and the FHE linear model.
Args:
X (numpy.ndarray): The input data.
y (numpy.ndarray): The target data. random_state (Optional[Union[int, numpy.random.RandomState, None]]): The random state. Defaults to None.
Returns: Tuple[SklearnLinearModelMixin, sklearn.linear_model.LinearRegression]: The FHE and sklearn LinearRegression.
method post_processing
Post-processing the predictions.
This step may include a dequantization of the inputs if not done previously, in particular within the client-server workflow.
Args:
y_preds (numpy.ndarray): The predictions to post-process.
already_dequantized (bool): Wether the inputs were already dequantized or not. Default to False.
Returns:
numpy.ndarray: The post-processed predictions.
method predict
Predict on user data.
Predict on user data using either the quantized clear model, implemented with tensors, or, if execute_in_fhe is set, using the compiled FHE circuit.
Args:
X (numpy.ndarray): Samples to predict.
execute_in_fhe (bool): If True, the inference will be executed in FHE. Default to False.
Returns:
numpy.ndarray: The prediction as ordinals.
method predict_proba
Predict class probabilities for samples.
Args:
X (numpy.ndarray): Samples to predict.
execute_in_fhe (bool): If True, the inference will be executed in FHE. Default to False.
Returns:
numpy.ndarray: Class probabilities for samples.
compilation_artifacts
(Optional[DebugArtifacts]): artifacts object to fill during compilation
show_mlir (bool): whether or not to show MLIR during the compilation
use_virtual_lib (bool): whether to compile using the virtual library that allows higher bitwidths
p_error (Optional[float]): probability of error of a PBS
**fit_params
: additional parameters that can be used during training, these are passed to the torch training interface
*args
: The arguments to pass to the sklearn linear model.
**kwargs: The keyword arguments to pass to the sklearn linear model.
compilation_artifacts
(Optional[DebugArtifacts]): artifacts object to fill during compilation
show_mlir (bool): whether or not to show MLIR during the compilation
use_virtual_lib (bool): set to True to use the so called virtual lib simulating FHE computation. Defaults to False
p_error (Optional[float]): probability of error of a PBS
*args
: args for super().fit
**kwargs: kwargs for super().fit
compilation_artifacts
(Optional[DebugArtifacts]): artifacts object to fill during compilation
show_mlir (bool): whether or not to show MLIR during the compilation
use_virtual_lib (bool): set to True to use the so called virtual lib simulating FHE computation. Defaults to False
p_error (Optional[float]): probability of error of a PBS
**kwargs
: args for super().fit
*args
: args for super().fit
**kwargs: kwargs for super().fit
compilation_artifacts
(Optional[DebugArtifacts]): artifacts object to fill during compilation
show_mlir (bool): whether or not to show MLIR during the compilation
use_virtual_lib (bool): set to True to use the so called virtual lib simulating FHE computation. Defaults to False
p_error (Optional[float]): probability of error of a PBS
**kwargs
: args for super().fit
*args
: args for super().fit
**kwargs: kwargs for super().fit
**kwargs: The keyword arguments to pass to the sklearn linear model.
compilation_artifacts
(Optional[DebugArtifacts]): Artifacts object to fill during compilation
show_mlir (bool): if set, the MLIR produced by the converter and which is going to be sent to the compiler backend is shown on the screen, e.g., for debugging or demo. Defaults to False.
use_virtual_lib (bool): whether to compile using the virtual library that allows higher bitwidths with simulated FHE computation. Defaults to False
p_error (Optional[float]): probability of error of a PBS
*args
: The arguments to pass to the sklearn linear model.
**kwargs: The keyword arguments to pass to the sklearn linear model.
*args
: The arguments to pass to the sklearn linear model. or not (False). Default to False.
*args: args for super().fit
**kwargs: kwargs for super().fit
**kwargs: The keyword arguments to pass to the sklearn linear model.
compilation_artifacts
(Optional[DebugArtifacts]): Artifacts object to fill during compilation
show_mlir (bool): if set, the MLIR produced by the converter and which is going to be sent to the compiler backend is shown on the screen, e.g., for debugging or demo. Defaults to False.
use_virtual_lib (bool): whether to compile using the virtual library that allows higher bitwidths with simulated FHE computation. Defaults to False
p_error (Optional[float]): probability of error of a PBS
*args
: The arguments to pass to the sklearn linear model.
**kwargs: The keyword arguments to pass to the sklearn linear model.
*args
: The arguments to pass to the sklearn linear model. or not (False). Default to False.
Quantized versions of the ONNX operators for post training quantization.
class QuantizedSigmoid
Quantized sigmoid op.
property op_type
Get the type of this operation.
Returns:
op_type (str): The type of this operation, in the ONNX referential
class QuantizedHardSigmoid
Quantized HardSigmoid op.
property op_type
Get the type of this operation.
Returns:
op_type (str): The type of this operation, in the ONNX referential
class QuantizedRelu
Quantized Relu op.
property op_type
Get the type of this operation.
Returns:
op_type (str): The type of this operation, in the ONNX referential
class QuantizedPRelu
Quantized PRelu op.
property op_type
Get the type of this operation.
Returns:
op_type (str): The type of this operation, in the ONNX referential
class QuantizedLeakyRelu
Quantized LeakyRelu op.
property op_type
Get the type of this operation.
Returns:
op_type (str): The type of this operation, in the ONNX referential
class QuantizedHardSwish
Quantized Hardswish op.
property op_type
Get the type of this operation.
Returns:
op_type (str): The type of this operation, in the ONNX referential
class QuantizedElu
Quantized Elu op.
property op_type
Get the type of this operation.
Returns:
op_type (str): The type of this operation, in the ONNX referential
class QuantizedSelu
Quantized Selu op.
property op_type
Get the type of this operation.
Returns:
op_type (str): The type of this operation, in the ONNX referential
class QuantizedCelu
Quantized Celu op.
property op_type
Get the type of this operation.
Returns:
op_type (str): The type of this operation, in the ONNX referential
class QuantizedClip
Quantized clip op.
property op_type
Get the type of this operation.
Returns:
op_type (str): The type of this operation, in the ONNX referential
class QuantizedRound
Quantized round op.
property op_type
Get the type of this operation.
Returns:
op_type (str): The type of this operation, in the ONNX referential
class QuantizedPow
Quantized pow op.
Only works for a float constant power. This operation will be fused to a (potentially larger) TLU.
property op_type
Get the type of this operation.
Returns:
op_type (str): The type of this operation, in the ONNX referential
class QuantizedGemm
Quantized Gemm op.
method __init__
property op_type
Get the type of this operation.
Returns:
op_type (str): The type of this operation, in the ONNX referential
method can_fuse
Determine if this op can be fused.
Gemm operation can not be fused since it must be performed over integer tensors and it combines different values of the input tensors.
Returns:
bool: False, this operation can not be fused as it adds different encrypted integers
method q_impl
class QuantizedMatMul
Quantized MatMul op.
method __init__
property op_type
Get the type of this operation.
Returns:
op_type (str): The type of this operation, in the ONNX referential
method can_fuse
Determine if this op can be fused.
Gemm operation can not be fused since it must be performed over integer tensors and it combines different values of the input tensors.
Returns:
bool: False, this operation can not be fused as it adds different encrypted integers
method q_impl
class QuantizedAdd
Quantized Addition operator.
Can add either two variables (both encrypted) or a variable and a constant
property op_type
Get the type of this operation.
Returns:
op_type (str): The type of this operation, in the ONNX referential
method can_fuse
Determine if this op can be fused.
Add operation can be computed in float and fused if it operates over inputs produced by a single integer tensor. For example the expression x + x * 1.75, where x is an encrypted tensor, can be computed with a single TLU.
Returns:
bool: Whether the number of integer input tensors allows computing this op as a TLU
method q_impl
class QuantizedTanh
Quantized Tanh op.
property op_type
Get the type of this operation.
Returns:
op_type (str): The type of this operation, in the ONNX referential
class QuantizedSoftplus
Quantized Softplus op.
property op_type
Get the type of this operation.
Returns:
op_type (str): The type of this operation, in the ONNX referential
class QuantizedExp
Quantized Exp op.
property op_type
Get the type of this operation.
Returns:
op_type (str): The type of this operation, in the ONNX referential
class QuantizedLog
Quantized Log op.
property op_type
Get the type of this operation.
Returns:
op_type (str): The type of this operation, in the ONNX referential
class QuantizedAbs
Quantized Abs op.
property op_type
Get the type of this operation.
Returns:
op_type (str): The type of this operation, in the ONNX referential
class QuantizedIdentity
Quantized Identity op.
property op_type
Get the type of this operation.
Returns:
op_type (str): The type of this operation, in the ONNX referential
method q_impl
class QuantizedReshape
Quantized Reshape op.
property op_type
Get the type of this operation.
Returns:
op_type (str): The type of this operation, in the ONNX referential
method q_impl
Reshape the input integer encrypted tensor.
Args:
q_inputs: an encrypted integer tensor at index 0 and one constant shape at index 1
attrs: additional optional reshape options
Returns:
result (QuantizedArray): reshaped encrypted integer tensor
class QuantizedConv
Quantized Conv op.
method __init__
Construct the quantized convolution operator and retrieve parameters.
Args:
n_bits_output: number of bits for the quantization of the outputs of this operator
int_input_names: names of integer tensors that are taken as input for this operation
property op_type
Get the type of this operation.
Returns:
op_type (str): The type of this operation, in the ONNX referential
method can_fuse
Determine if this op can be fused.
Conv operation can not be fused since it must be performed over integer tensors and it combines different elements of the input tensors.
Returns:
bool: False, this operation can not be fused as it adds different encrypted integers
method q_impl
Compute the quantized convolution between two quantized tensors.
Allows an optional quantized bias.
Args:
q_inputs: input tuple, contains
x (numpy.ndarray): input data. Shape is N x C x H x W for 2d
Returns:
res (QuantizedArray): result of the quantized integer convolution
class QuantizedAvgPool
Quantized Average Pooling op.
method __init__
property op_type
Get the type of this operation.
Returns:
op_type (str): The type of this operation, in the ONNX referential
method can_fuse
Determine if this op can be fused.
Avg Pooling operation can not be fused since it must be performed over integer tensors and it combines different elements of the input tensors.
Returns:
bool: False, this operation can not be fused as it adds different encrypted integers
method q_impl
class QuantizedPad
Quantized Padding op.
method __init__
property op_type
Get the type of this operation.
Returns:
op_type (str): The type of this operation, in the ONNX referential
method can_fuse
Determine if this op can be fused.
Pad operation can not be fused since it must be performed over integer tensors.
Returns:
bool: False, this operation can not be fused as it is manipulates integer tensors
class QuantizedWhere
Where operator on quantized arrays.
Supports only constants for the results produced on the True/False branches.
method __init__
property op_type
Get the type of this operation.
Returns:
op_type (str): The type of this operation, in the ONNX referential
class QuantizedCast
Cast the input to the required data type.
In FHE we only support a limited number of output types. Booleans are cast to integers.
property op_type
Get the type of this operation.
Returns:
op_type (str): The type of this operation, in the ONNX referential
class QuantizedGreater
Comparison operator >.
Only supports comparison with a constant.
method __init__
property op_type
Get the type of this operation.
Returns:
op_type (str): The type of this operation, in the ONNX referential
class QuantizedGreaterOrEqual
Comparison operator >=.
Only supports comparison with a constant.
method __init__
property op_type
Get the type of this operation.
Returns:
op_type (str): The type of this operation, in the ONNX referential
class QuantizedLess
Comparison operator <.
Only supports comparison with a constant.
method __init__
property op_type
Get the type of this operation.
Returns:
op_type (str): The type of this operation, in the ONNX referential
class QuantizedLessOrEqual
Comparison operator <=.
Only supports comparison with a constant.
method __init__
property op_type
Get the type of this operation.
Returns:
op_type (str): The type of this operation, in the ONNX referential
class QuantizedOr
Or operator ||.
This operation is not really working as a quantized operation. It just works when things got fused, as in e.g. Act(x) = x || (x + 42))
property op_type
Get the type of this operation.
Returns:
op_type (str): The type of this operation, in the ONNX referential
class QuantizedDiv
Div operator /.
This operation is not really working as a quantized operation. It just works when things got fused, as in e.g. Act(x) = 1000 / (x + 42))
property op_type
Get the type of this operation.
Returns:
op_type (str): The type of this operation, in the ONNX referential
class QuantizedMul
Multiplication operator.
Only multiplies an encrypted tensor with a float constant for now. This operation will be fused to a (potentially larger) TLU.
property op_type
Get the type of this operation.
Returns:
op_type (str): The type of this operation, in the ONNX referential
class QuantizedSub
Subtraction operator.
This works the same as addition on both encrypted - encrypted and on encrypted - constant.
property op_type
Get the type of this operation.
Returns:
op_type (str): The type of this operation, in the ONNX referential
method can_fuse
Determine if this op can be fused.
Add operation can be computed in float and fused if it operates over inputs produced by a single integer tensor. For example the expression x + x * 1.75, where x is an encrypted tensor, can be computed with a single TLU.
Returns:
bool: Whether the number of integer input tensors allows computing this op as a TLU
method q_impl
class QuantizedBatchNormalization
Quantized Batch normalization with encrypted input and in-the-clear normalization params.
property op_type
Get the type of this operation.
Returns:
op_type (str): The type of this operation, in the ONNX referential
class QuantizedFlatten
Quantized flatten for encrypted inputs.
property op_type
Get the type of this operation.
Returns:
op_type (str): The type of this operation, in the ONNX referential
method can_fuse
Determine if this op can be fused.
Flatten operation can not be fused since it must be performed over integer tensors.
Returns:
bool: False, this operation can not be fused as it is manipulates integer tensors.
method q_impl
Flatten the input integer encrypted tensor.
Args:
q_inputs: an encrypted integer tensor at index 0
attrs: contains axis attribute
Returns:
result (QuantizedArray): reshaped encrypted integer tensor
class QuantizedReduceSum
ReduceSum with encrypted input.
This operator is currently an experimental feature.
method __init__
Construct the quantized ReduceSum operator and retrieve parameters.
Args:
n_bits_output (int): Number of bits for the operator's quantization of outputs.
int_input_names (Optional[Set[str]]): Names of input integer tensors. Default to None.
property op_type
Get the type of this operation.
Returns:
op_type (str): The type of this operation, in the ONNX referential
method calibrate
Create corresponding QuantizedArray for the output of the activation function.
numpy.ndarray: the output values for the provided calibration samples.
method q_impl
Sum the encrypted tensor's values over axis 1.
Args:
q_inputs (QuantizedArray): An encrypted integer tensor at index 0.
attrs (Dict): Contains axis attribute.
Returns:
(QuantizedArray): The sum of all values along axis 1 as an encrypted integer tensor.
method tree_sum
Large sum without overflow (only MSB remains).
Args:
input_qarray: Enctyped integer tensor.
is_calibration: Whether we are calibrating the tree sum. If so, it will create all the quantizers for the downscaling.
Returns:
(numpy.ndarray): The MSB (based on the precision self.n_bits) of the integers sum.
class QuantizedErf
Quantized erf op.
property op_type
Get the type of this operation.
Returns:
op_type (str): The type of this operation, in the ONNX referential
class QuantizedNot
Quantized Not op.
property op_type
Get the type of this operation.
Returns:
op_type (str): The type of this operation, in the ONNX referential
class QuantizedBrevitasQuant
Brevitas uniform quantization with encrypted input.
method __init__
Construct the Brevitas quantization operator.
Args:
n_bits_output (int): Number of bits for the operator's quantization of outputs. Not used, will be overridden by the bit_width in ONNX
int_input_names (Optional[Set[str]]): Names of input integer tensors. Default to None.
property op_type
Get the type of this operation.
Returns:
op_type (str): The type of this operation, in the ONNX referential
method q_impl
Quantize values.
Args:
q_inputs: an encrypted integer tensor at index 0 and one constant shape at index 1
attrs: additional optional reshape options
Returns:
result (QuantizedArray): reshaped encrypted integer tensor
class QuantizedTranspose
Transpose operator for quantized inputs.
This operator performs quantization, transposes the encrypted data, then dequantizes again.
property op_type
Get the type of this operation.
Returns:
op_type (str): The type of this operation, in the ONNX referential
method q_impl
Reshape the input integer encrypted tensor.
Args:
q_inputs: an encrypted integer tensor at index 0 and one constant shape at index 1
attrs: additional optional reshape options
Returns:
result (QuantizedArray): reshaped encrypted integer tensor
class QuantizedFloor
Quantized Floor op.
property op_type
Get the type of this operation.
Returns:
op_type (str): The type of this operation, in the ONNX referential
class QuantizedMax
Quantized Max op.
property op_type
Get the type of this operation.
Returns:
op_type (str): The type of this operation, in the ONNX referential
class QuantizedMin
Quantized Min op.
property op_type
Get the type of this operation.
Returns:
op_type (str): The type of this operation, in the ONNX referential
class QuantizedNeg
Quantized Neg op.
property op_type
Get the type of this operation.
Returns:
op_type (str): The type of this operation, in the ONNX referential
class QuantizedSign
Quantized Neg op.
property op_type
Get the type of this operation.
Returns:
op_type (str): The type of this operation, in the ONNX referential
constant_inputs
: the weights and activations
input_quant_opts: options for the input quantizer
attrs: convolution options
dilations (Tuple[int]): dilation of the kernel, default 1 on all dimensions.
group (int): number of convolution groups, default 1
kernel_shape (Tuple[int]): shape of the kernel. Should have 2 elements for 2d conv
pads (Tuple[int]): padding in ONNX format (begin, end) on each axis
strides (Tuple[int]): stride of the convolution on each axis
w
(numpy.ndarray): weights tensor. Shape is (O x I x Kh x Kw) for 2d
b (numpy.ndarray, Optional): bias tensor, Shape is (O,)
attrs: convolution options handled in constructor
constant_inputs
(Optional[Dict]): Input constant tensor.
axes (Optional[numpy.ndarray]): Array of integers along which to reduce. The default is to reduce over all the dimensions of the input tensor if 'noop_with_empty_axes' is false, else act as an Identity op when 'noop_with_empty_axes' is true. Accepted range is [-r, r-1] where r = rank(data). Default to None.
input_quant_opts (Optional[QuantizationOptions]): Options for the input quantizer. Default to None.
attrs (dict): RecuseSum options.
keepdims (int): Keep the reduced dimension or not, 1 means keeping the input dimension, 0 will reduce it along the given axis. Default to 1.
noop_with_empty_axes (int): Defines behavior if 'axes' is empty or set to None. Default behavior with 0 is to reduce all axes. When axes is empty and this attribute is set to true 1, input tensor will not be reduced, and the output tensor would be equivalent to input tensor. Default to 0.
bit_width (int): Number of bits of the integer representation
input_quant_opts (Optional[QuantizationOptions]): Options for the input quantizer. Default to None. attrs (dict):
rounding_mode (str): Rounding mode (default and only accepted option is "ROUND")
signed (int): Whether this op quantizes to signed integers (default 1),
narrow (int): Whether this op quantizes to a narrow range of integers e.g. [-2n_bits-1 .. 2n_bits-1] (default 0),
concrete.ml.onnx.ops_impl
module concrete.ml.onnx.ops_impl
ONNX ops implementation in python + numpy.
function cast_to_float
Cast values to floating points.
Args:
inputs (Tuple[numpy.ndarray]): The values to consider.
Returns:
Tuple[numpy.ndarray]: The float values.
function onnx_func_raw_args
Decorate a numpy onnx function to flag the raw/non quantized inputs.
Args:
*args (tuple[Any]): function argument names
Returns:
result (ONNXMixedFunction): wrapped numpy function with a list of mixed arguments
function numpy_where_body
Compute the equivalent of numpy.where.
This function is not mapped to any ONNX operator (as opposed to numpy_where). It is usable by functions which are mapped to ONNX operators, e.g. numpy_div or numpy_where.
Args:
c (numpy.ndarray): Condition operand.
t (numpy.ndarray): True operand.
Returns:
numpy.ndarray: numpy.where(c, t, f)
function numpy_where
Compute the equivalent of numpy.where.
Args:
c (numpy.ndarray): Condition operand.
t (numpy.ndarray): True operand.
Returns:
numpy.ndarray: numpy.where(c, t, f)
function numpy_add
Compute add in numpy according to ONNX spec.
See https://github.com/onnx/onnx/blob/main/docs/Changelog.md#Add-13
Args:
a (numpy.ndarray): First operand.
b (numpy.ndarray): Second operand.
Returns:
Tuple[numpy.ndarray]: Result, has same element type as two inputs
function numpy_constant
Return the constant passed as a kwarg.
See https://github.com/onnx/onnx/blob/main/docs/Changelog.md#Constant-13
Args:
**kwargs: keyword arguments
Returns:
Any: The stored constant.
function numpy_matmul
Compute matmul in numpy according to ONNX spec.
See https://github.com/onnx/onnx/blob/main/docs/Changelog.md#MatMul-13
Args:
a (numpy.ndarray): N-dimensional matrix A
b (numpy.ndarray): N-dimensional matrix B
Returns:
Tuple[numpy.ndarray]: Matrix multiply results from A * B
function numpy_relu
Compute relu in numpy according to ONNX spec.
See https://github.com/onnx/onnx/blob/main/docs/Changelog.md#Relu-14
Args:
x (numpy.ndarray): Input tensor
Returns:
Tuple[numpy.ndarray]: Output tensor
function numpy_sigmoid
Compute sigmoid in numpy according to ONNX spec.
See https://github.com/onnx/onnx/blob/main/docs/Changelog.md#Sigmoid-13
Args:
x (numpy.ndarray): Input tensor
Returns:
Tuple[numpy.ndarray]: Output tensor
function numpy_softmax
Compute softmax in numpy according to ONNX spec.
Softmax is currently not supported in FHE.
See https://github.com/onnx/onnx/blob/main/docs/Changelog.md#softmax-13
Args:
x (numpy.ndarray): Input tensor
axis (None, int, tuple of ints): Axis or axes along which a softmax's sum is performed. If None, it will sum all of the elements of the input array. If axis is negative it counts from the last to the first axis. Default to 1.
Returns:
Tuple[numpy.ndarray]: Output tensor
function numpy_cos
Compute cos in numpy according to ONNX spec.
See https://github.com/onnx/onnx/blob/main/docs/Changelog.md#Cos-7
Args:
x (numpy.ndarray): Input tensor
Returns:
Tuple[numpy.ndarray]: Output tensor
function numpy_cosh
Compute cosh in numpy according to ONNX spec.
See https://github.com/onnx/onnx/blob/main/docs/Changelog.md#Cosh-9
Args:
x (numpy.ndarray): Input tensor
Returns:
Tuple[numpy.ndarray]: Output tensor
function numpy_sin
Compute sin in numpy according to ONNX spec.
See https://github.com/onnx/onnx/blob/main/docs/Changelog.md#Sin-7
Args:
x (numpy.ndarray): Input tensor
Returns:
Tuple[numpy.ndarray]: Output tensor
function numpy_sinh
Compute sinh in numpy according to ONNX spec.
See https://github.com/onnx/onnx/blob/main/docs/Changelog.md#Sinh-9
Args:
x (numpy.ndarray): Input tensor
Returns:
Tuple[numpy.ndarray]: Output tensor
function numpy_tan
Compute tan in numpy according to ONNX spec.
See https://github.com/onnx/onnx/blob/main/docs/Changelog.md#Tan-7
Args:
x (numpy.ndarray): Input tensor
Returns:
Tuple[numpy.ndarray]: Output tensor
function numpy_tanh
Compute tanh in numpy according to ONNX spec.
See https://github.com/onnx/onnx/blob/main/docs/Changelog.md#Tanh-13
Args:
x (numpy.ndarray): Input tensor
Returns:
Tuple[numpy.ndarray]: Output tensor
function numpy_acos
Compute acos in numpy according to ONNX spec.
See https://github.com/onnx/onnx/blob/main/docs/Changelog.md#Acos-7
Args:
x (numpy.ndarray): Input tensor
Returns:
Tuple[numpy.ndarray]: Output tensor
function numpy_acosh
Compute acosh in numpy according to ONNX spec.
See https://github.com/onnx/onnx/blob/main/docs/Changelog.md#Acosh-9
Args:
x (numpy.ndarray): Input tensor
Returns:
Tuple[numpy.ndarray]: Output tensor
function numpy_asin
Compute asin in numpy according to ONNX spec.
See https://github.com/onnx/onnx/blob/main/docs/Changelog.md#Asin-7
Args:
x (numpy.ndarray): Input tensor
Returns:
Tuple[numpy.ndarray]: Output tensor
function numpy_asinh
Compute sinh in numpy according to ONNX spec.
See https://github.com/onnx/onnx/blob/main/docs/Changelog.md#Asinh-9
Args:
x (numpy.ndarray): Input tensor
Returns:
Tuple[numpy.ndarray]: Output tensor
function numpy_atan
Compute atan in numpy according to ONNX spec.
See https://github.com/onnx/onnx/blob/main/docs/Changelog.md#Atan-7
Args:
x (numpy.ndarray): Input tensor
Returns:
Tuple[numpy.ndarray]: Output tensor
function numpy_atanh
Compute atanh in numpy according to ONNX spec.
See https://github.com/onnx/onnx/blob/main/docs/Changelog.md#Atanh-9
Args:
x (numpy.ndarray): Input tensor
Returns:
Tuple[numpy.ndarray]: Output tensor
function numpy_elu
Compute elu in numpy according to ONNX spec.
See https://github.com/onnx/onnx/blob/main/docs/Changelog.md#Elu-6
Args:
x (numpy.ndarray): Input tensor
alpha (float): Coefficient
Returns:
Tuple[numpy.ndarray]: Output tensor
function numpy_selu
Compute selu in numpy according to ONNX spec.
See https://github.com/onnx/onnx/blob/main/docs/Changelog.md#Selu-6
Args:
x (numpy.ndarray): Input tensor
alpha (float): Coefficient
Returns:
Tuple[numpy.ndarray]: Output tensor
function numpy_celu
Compute celu in numpy according to ONNX spec.
See https://github.com/onnx/onnx/blob/main/docs/Changelog.md#Celu-12
Args:
x (numpy.ndarray): Input tensor
alpha (float): Coefficient
Returns:
Tuple[numpy.ndarray]: Output tensor
function numpy_leakyrelu
Compute leakyrelu in numpy according to ONNX spec.
See https://github.com/onnx/onnx/blob/main/docs/Changelog.md#LeakyRelu-6
Args:
x (numpy.ndarray): Input tensor
alpha (float): Coefficient
Returns:
Tuple[numpy.ndarray]: Output tensor
function numpy_thresholdedrelu
Compute thresholdedrelu in numpy according to ONNX spec.
See https://github.com/onnx/onnx/blob/main/docs/Changelog.md#ThresholdedRelu-10
Args:
x (numpy.ndarray): Input tensor
alpha (float): Coefficient
Returns:
Tuple[numpy.ndarray]: Output tensor
function numpy_hardsigmoid
Compute hardsigmoid in numpy according to ONNX spec.
See https://github.com/onnx/onnx/blob/main/docs/Changelog.md#HardSigmoid-6
Args:
x (numpy.ndarray): Input tensor
alpha (float): Coefficient
Returns:
Tuple[numpy.ndarray]: Output tensor
function numpy_softplus
Compute softplus in numpy according to ONNX spec.
See https://github.com/onnx/onnx/blob/main/docs/Changelog.md#Softplus-1
Args:
x (numpy.ndarray): Input tensor
Returns:
Tuple[numpy.ndarray]: Output tensor
function numpy_abs
Compute abs in numpy according to ONNX spec.
See https://github.com/onnx/onnx/blob/main/docs/Changelog.md#Abs-13
Args:
x (numpy.ndarray): Input tensor
Returns:
Tuple[numpy.ndarray]: Output tensor
function numpy_div
Compute div in numpy according to ONNX spec.
See https://github.com/onnx/onnx/blob/main/docs/Changelog.md#Div-14
Args:
a (numpy.ndarray): Input tensor
b (numpy.ndarray): Input tensor
Returns:
Tuple[numpy.ndarray]: Output tensor
function numpy_mul
Compute mul in numpy according to ONNX spec.
See https://github.com/onnx/onnx/blob/main/docs/Changelog.md#Mul-14
Args:
a (numpy.ndarray): Input tensor
b (numpy.ndarray): Input tensor
Returns:
Tuple[numpy.ndarray]: Output tensor
function numpy_sub
Compute sub in numpy according to ONNX spec.
See https://github.com/onnx/onnx/blob/main/docs/Changelog.md#Sub-14
Args:
a (numpy.ndarray): Input tensor
b (numpy.ndarray): Input tensor
Returns:
Tuple[numpy.ndarray]: Output tensor
function numpy_log
Compute log in numpy according to ONNX spec.
See https://github.com/onnx/onnx/blob/main/docs/Changelog.md#Log-13
Args:
x (numpy.ndarray): Input tensor
Returns:
Tuple[numpy.ndarray]: Output tensor
function numpy_erf
Compute erf in numpy according to ONNX spec.
See https://github.com/onnx/onnx/blob/main/docs/Changelog.md#Erf-13
Args:
x (numpy.ndarray): Input tensor
Returns:
Tuple[numpy.ndarray]: Output tensor
function numpy_hardswish
Compute hardswish in numpy according to ONNX spec.
See https://github.com/onnx/onnx/blob/main/docs/Changelog.md#hardswish-14
Args:
x (numpy.ndarray): Input tensor
Returns:
Tuple[numpy.ndarray]: Output tensor
function numpy_exp
Compute exponential in numpy according to ONNX spec.
See https://github.com/onnx/onnx/blob/main/docs/Changelog.md#Exp-13
Args:
x (numpy.ndarray): Input tensor
Returns:
Tuple[numpy.ndarray]: The exponential of the input tensor computed element-wise
function numpy_equal
Compute equal in numpy according to ONNX spec.
See https://github.com/onnx/onnx/blob/main/docs/Changelog.md#Equal-11
Args:
x (numpy.ndarray): Input tensor
y (numpy.ndarray): Input tensor
Returns:
Tuple[numpy.ndarray]: Output tensor
function numpy_not
Compute not in numpy according to ONNX spec.
See https://github.com/onnx/onnx/blob/main/docs/Changelog.md#Not-1
Args:
x (numpy.ndarray): Input tensor
Returns:
Tuple[numpy.ndarray]: Output tensor
function numpy_not_float
Compute not in numpy according to ONNX spec and cast outputs to floats.
See https://github.com/onnx/onnx/blob/main/docs/Changelog.md#Not-1
Args:
x (numpy.ndarray): Input tensor
Returns:
Tuple[numpy.ndarray]: Output tensor
function numpy_greater
Compute greater in numpy according to ONNX spec.
See https://github.com/onnx/onnx/blob/main/docs/Changelog.md#Greater-13
Args:
x (numpy.ndarray): Input tensor
y (numpy.ndarray): Input tensor
Returns:
Tuple[numpy.ndarray]: Output tensor
function numpy_greater_float
Compute greater in numpy according to ONNX spec and cast outputs to floats.
See https://github.com/onnx/onnx/blob/main/docs/Changelog.md#Greater-13
Args:
x (numpy.ndarray): Input tensor
y (numpy.ndarray): Input tensor
Returns:
Tuple[numpy.ndarray]: Output tensor
function numpy_greater_or_equal
Compute greater or equal in numpy according to ONNX spec.
See https://github.com/onnx/onnx/blob/main/docs/Changelog.md#GreaterOrEqual-12
Args:
x (numpy.ndarray): Input tensor
y (numpy.ndarray): Input tensor
Returns:
Tuple[numpy.ndarray]: Output tensor
function numpy_greater_or_equal_float
Compute greater or equal in numpy according to ONNX specs and cast outputs to floats.
See https://github.com/onnx/onnx/blob/main/docs/Changelog.md#GreaterOrEqual-12
Args:
x (numpy.ndarray): Input tensor
y (numpy.ndarray): Input tensor
Returns:
Tuple[numpy.ndarray]: Output tensor
function numpy_less
Compute less in numpy according to ONNX spec.
See https://github.com/onnx/onnx/blob/main/docs/Changelog.md#Less-13
Args:
x (numpy.ndarray): Input tensor
y (numpy.ndarray): Input tensor
Returns:
Tuple[numpy.ndarray]: Output tensor
function numpy_less_float
Compute less in numpy according to ONNX spec and cast outputs to floats.
See https://github.com/onnx/onnx/blob/main/docs/Changelog.md#Less-13
Args:
x (numpy.ndarray): Input tensor
y (numpy.ndarray): Input tensor
Returns:
Tuple[numpy.ndarray]: Output tensor
function numpy_less_or_equal
Compute less or equal in numpy according to ONNX spec.
See https://github.com/onnx/onnx/blob/main/docs/Changelog.md#LessOrEqual-12
Args:
x (numpy.ndarray): Input tensor
y (numpy.ndarray): Input tensor
Returns:
Tuple[numpy.ndarray]: Output tensor
function numpy_less_or_equal_float
Compute less or equal in numpy according to ONNX spec and cast outputs to floats.
See https://github.com/onnx/onnx/blob/main/docs/Changelog.md#LessOrEqual-12
Args:
x (numpy.ndarray): Input tensor
y (numpy.ndarray): Input tensor
Returns:
Tuple[numpy.ndarray]: Output tensor
function numpy_identity
Compute identity in numpy according to ONNX spec.
See https://github.com/onnx/onnx/blob/main/docs/Changelog.md#Identity-14
Args:
x (numpy.ndarray): Input tensor
Returns:
Tuple[numpy.ndarray]: Output tensor
function numpy_transpose
Transpose in numpy according to ONNX spec.
See https://github.com/onnx/onnx/blob/main/docs/Changelog.md#Transpose-13
Args:
x (numpy.ndarray): Input tensor
perm (numpy.ndarray): Permutation of the axes
Returns:
Tuple[numpy.ndarray]: Output tensor
function numpy_avgpool
Compute Average Pooling using Torch.
Currently supports 2d average pooling with torch semantics. This function is ONNX compatible.
to (int): integer value of the onnx.TensorProto DataType enum
Returns:
result (numpy.ndarray): a tensor with the required data type
function numpy_batchnorm
Compute the batch normalization of the input tensor.
This can be expressed as:
Y = (X - input_mean) / sqrt(input_var + epsilon) * scale + B
See https://github.com/onnx/onnx/blob/main/docs/Changelog.md#BatchNormalization-14
Args:
x (numpy.ndarray): tensor to normalize, dimensions are in the form of (N,C,D1,D2,...,Dn), where N is the batch size, C is the number of channels.
scale (numpy.ndarray): scale tensor of shape (C,)
Returns:
numpy.ndarray: Normalized tensor
function numpy_flatten
Flatten a tensor into a 2d array.
See https://github.com/onnx/onnx/blob/main/docs/Changelog.md#Flatten-13.
Args:
x (numpy.ndarray): tensor to flatten
axis (int): axis after which all dimensions will be flattened (axis=0 gives a 1D output)
Returns:
result: flattened tensor
function numpy_or
Compute or in numpy according to ONNX spec.
See https://github.com/onnx/onnx/blob/main/docs/Changelog.md#Or-7
Args:
a (numpy.ndarray): Input tensor
b (numpy.ndarray): Input tensor
Returns:
Tuple[numpy.ndarray]: Output tensor
function numpy_or_float
Compute or in numpy according to ONNX spec and cast outputs to floats.
See https://github.com/onnx/onnx/blob/main/docs/Changelog.md#Or-7
Args:
a (numpy.ndarray): Input tensor
b (numpy.ndarray): Input tensor
Returns:
Tuple[numpy.ndarray]: Output tensor
function numpy_round
Compute round in numpy according to ONNX spec.
See https://github.com/onnx/onnx/blob/main/docs/Changelog.md#Round-11 Remark that ONNX Round operator is actually a rint, since the number of decimals is forced to be 0
Args:
a (numpy.ndarray): Input tensor whose elements to be rounded.
Returns:
Tuple[numpy.ndarray]: Output tensor with rounded input elements.
function numpy_pow
Compute pow in numpy according to ONNX spec.
See https://github.com/onnx/onnx/blob/main/docs/Changelog.md#Pow-13
Args:
a (numpy.ndarray): Input tensor whose elements to be raised.
b (numpy.ndarray): The power to which we want to raise.
Returns:
Tuple[numpy.ndarray]: Output tensor.
function numpy_floor
Compute Floor in numpy according to ONNX spec.
See https://github.com/onnx/onnx/blob/main/docs/Changelog.md#Floor-1
Args:
x (numpy.ndarray): Input tensor
Returns:
Tuple[numpy.ndarray]: Output tensor
function numpy_max
Compute Max in numpy according to ONNX spec.
Computes the max between the first input and a float constant.
See https://github.com/onnx/onnx/blob/main/docs/Changelog.md#Max-1
Args:
a (numpy.ndarray): Input tensor
b (numpy.ndarray): Constant tensor to compare to the first input
Returns:
Tuple[numpy.ndarray]: Output tensor
function numpy_min
Compute Min in numpy according to ONNX spec.
Computes the minimum between the first input and a float constant.
See https://github.com/onnx/onnx/blob/main/docs/Changelog.md#Max-1
Args:
a (numpy.ndarray): Input tensor
b (numpy.ndarray): Constant tensor to compare to the first input
Returns:
Tuple[numpy.ndarray]: Output tensor
function numpy_sign
Compute Sign in numpy according to ONNX spec.
See https://github.com/onnx/onnx/blob/main/docs/Changelog.md#Sign-9
Args:
x (numpy.ndarray): Input tensor
Returns:
Tuple[numpy.ndarray]: Output tensor
function numpy_neg
Compute Negative in numpy according to ONNX spec.
See https://github.com/onnx/onnx/blob/main/docs/Changelog.md#Sign-9
Args:
x (numpy.ndarray): Input tensor
Returns:
Tuple[numpy.ndarray]: Output tensor
class ONNXMixedFunction
A mixed quantized-raw valued onnx function.
ONNX functions will take inputs which can be either quantized or float. Some functions only take quantized inputs, but some functions take both types. For mixed functions we need to tag the parameters that do not need quantization. Thus quantized ops can know which inputs are not QuantizedArray and we avoid unnecessary wrapping of float values as QuantizedArrays.
method __init__
Create the mixed function and raw parameter list.
Args:
function (Any): function to be decorated
non_quant_params: Set[str]: set of parameters that will not be quantized (stored as numpy.ndarray)
There are three ways to contribute to Concrete-ML:
You can open issues to report bugs and typos and to suggest ideas.
You can ask to become an official contributor by emailing [email protected]. Only approved contributors can send pull requests (PR), so please make sure to get in touch before you do.
You can also provide new tutorials or use-cases, showing what can be done with the library. The more examples we have, the better and clearer it is for the other users.
1. Creating a new branch
Concrete-ML uses a consistent branch naming scheme, and you are expected to follow it as well. Here is the format, along with some examples:
e.g.
2. Before committing
2.1 Conformance
Each commit to Concrete-ML should conform to the standards of the project. You can let the development tools fix some issues automatically with the following command:
Conformance can be checked using the following command:
2.2 Testing
Your code must be well documented, containing tests and not breaking other tests:
You need to make sure you get 100% code coverage. The make pytest command checks that by default and will fail with a coverage report at the end should some lines of your code not be executed during testing.
If your coverage is below 100%, you should write more tests and then create the pull request. If you ignore this warning and create the PR, GitHub actions will fail and your PR will not be merged.
There may be cases where covering your code is not possible (an exception that cannot be triggered in normal execution circumstances). In those cases, you may be allowed to disable coverage for some specific lines. This should be the exception rather than the rule, and reviewers will ask why some lines are not covered. If it appears they can be covered, then the PR won't be accepted in that state.
3. Committing
Concrete-ML uses a consistent commit naming scheme, and you are expected to follow it as well (the CI will make sure you do). The accepted format can be printed to your terminal by running:
e.g.
To learn more about conventional commits, check page. Just a reminder that commit messages are checked in the comformance step and are rejected if they don't follow the rules.
4. Rebasing
You should rebase on top of the main branch before you create your pull request. Merge commits are not allowed, so rebasing on main before pushing gives you the best chance of avoiding having to rewrite parts of your PR later if conflicts arise with other PRs being merged. After you commit your changes to your new branch, you can use the following commands to rebase:
You can learn more about rebasing .
5. Releases
Before any final release, Concrete-ML contributors go through a release candidate (RC) cycle. The idea is that once the codebase and documentations look ready for a release, you create an RC release by opening an issue with the release template , starting with version vX.Y.Zrc1 and then with versions vX.Y.Zrc2, vX.Y.Zrc3...
Once the last RC is deemed ready, open an issue with the release template using the last RC version from which you remove the rc? part (i.e. v12.67.19 if your last RC version was v12.67.19-rc4) on .
git commit -m "feat: implement bounds checking"
git commit -m "feat(debugging): add an helper function to draw intermediate representation"
git commit -m "fix(tracing): fix a bug that crashed PyTorch tracer"
# fetch the list of active remote branches
git fetch --all --prune
# checkout to main
git checkout main
# pull the latest changes to main (--ff-only is there to prevent accidental commits to main)
git pull --ff-only
# checkout back to your branch
git checkout $YOUR_BRANCH
# rebase on top of main branch
git rebase main
# If there are conflicts during the rebase, resolve them
# and continue the rebase with the following command
git rebase --continue
# push the latest version of the local branch to remote
git push --force