Quantize a deep neural network to 8-bit scaled integer data types
Use the dlquantizer object to reduce the memory requirement of a
deep neural network by quantizing weights, biases, and activations to 8-bit scaled integer
data types.
quantObj = dlquantizer(net)dlquantizer object for the specified network.
quantObj = dlquantizer(net,Name,Value)dlquantizer object for the specified network, with additional
options specified by one or more name-value pair arguments.
Use dlquantizer to create an quantized network for FPGA or GPU
deployment. To learn about the products required to quantize and deploy the deep learning
network to an FPGA or GPU environment, see Quantization Workflow Prerequisites .
net — Pretrained neural networkDAGNetwork object | SeriesNetwork object | yolov2ObjectDetector object | ssdObjectDetector objectPretrained neural network, specified as a DAGNetwork,
SeriesNetwork, yolov2ObjectDetector (Computer Vision Toolbox), or a ssdObjectDetector (Computer Vision Toolbox) object.
Quantization of ssdObjectDetector (Computer Vision Toolbox) networks requires the
ExecutionEnvironment property to be set to
'FPGA'.
NetworkObject — Pretrained neural networkDAGNetwork object | SeriesNetwork object | yolov2ObjectDetector object | ssdObjectDetector objectPretrained neural network, specified as a DAGNetwork,
SeriesNetwork,
yolov2ObjectDetector (Computer Vision Toolbox), or a ssdObjectDetector (Computer Vision Toolbox) object.
Quantization of ssdObjectDetector (Computer Vision Toolbox) networks requires the
ExecutionEnvironment property to be set to
'FPGA'.
ExecutionEnvironment — Execution environmentSpecify the execution environment for the quantized network. When this parameter is not specified the default execution environment is GPU. To learn about the products required to quantize and deploy the deep learning network to an FPGA or GPU environment, see Quantization Workflow Prerequisites .
Example: 'ExecutionEnvironment','FPGA'
This example shows how to specify an FPGA execution environment.
net = vgg19; quantobj = dlquantizer(net,'ExecutionEnvironment','FPGA');
This example shows how to quantize learnable parameters in the
convolution layers of a neural network, and explore the behavior of the quantized
network. In this example, you quantize the squeezenet neural network
after retraining the network to classify new images according to the Train Deep Learning Network to Classify New Images example. In this
example, the memory required for the network is reduced approximately 75% through
quantization while the accuracy of the network is not affected.
Load the pretrained network.
net
net =
DAGNetwork with properties:
Layers: [68x1 nnet.cnn.layer.Layer]
Connections: [75x2 table]
InputNames: {'data'}
OutputNames: {'new_classoutput'}Define calibration and validation data to use for quantization.
The calibration data is used to collect the dynamic ranges of the weights and biases in the convolution and fully connected layers of the network and the dynamic ranges of the activations in all layers of the network. For the best quantization results, the calibration data must be representative of inputs to the network.
The validation data is used to test the network after quantization to understand the effects of the limited range and precision of the quantized convolution layers in the network.
In this example, use the images in the MerchData data set.
Define an augmentedImageDatastore object to resize the data for the
network. Then, split the data into calibration and validation data sets.
unzip('MerchData.zip'); imds = imageDatastore('MerchData', ... 'IncludeSubfolders',true, ... 'LabelSource','foldernames'); [calData, valData] = splitEachLabel(imds, 0.7, 'randomized'); aug_calData = augmentedImageDatastore([227 227], calData); aug_valData = augmentedImageDatastore([227 227], valData);
Create a dlquantizer object and specify the network to
quantize.
quantObj = dlquantizer(net);
Define a metric function to use to compare the behavior of the network before and after quantization. Save this function in a local file.
function accuracy = hComputeModelAccuracy(predictionScores, net, dataStore) %% Computes model-level accuracy statistics % Load ground truth tmp = readall(dataStore); groundTruth = tmp.response; % Compare with predicted label with actual ground truth predictionError = {}; for idx=1:numel(groundTruth) [~, idy] = max(predictionScores(idx,:)); yActual = net.Layers(end).Classes(idy); predictionError{end+1} = (yActual == groundTruth(idx)); %#ok end % Sum all prediction errors. predictionError = [predictionError{:}]; accuracy = sum(predictionError)/numel(predictionError); end
Specify the metric function in a dlquantizationOptions
object.
quantOpts = dlquantizationOptions('MetricFcn', ... {@(x)hComputeModelAccuracy(x, net, aug_valData)});
Use the calibrate function to exercise the network with sample
inputs and collect range information. The calibrate function
exercises the network and collects the dynamic ranges of the weights and biases in
the convolution and fully connected layers of the network and the dynamic ranges of
the activations in all layers of the network. The function returns a table. Each row
of the table contains range information for a learnable parameter of the optimized
network.
calResults = calibrate(quantObj, aug_calData)
calResults =
95x5 table
Optimized Layer Name Network Layer Name Learnables / Activations MinValue MaxValue
__________________________________________________ _________________________ ________________________ __________ ___________
{'conv1_relu_conv1_Weights' } {'relu_conv1' } "Weights" -0.91985 0.88489
{'conv1_relu_conv1_Bias' } {'relu_conv1' } "Bias" -0.07925 0.26343
{'fire2-squeeze1x1_fire2-relu_squeeze1x1_Weights'} {'fire2-relu_squeeze1x1'} "Weights" -1.38 1.2477
{'fire2-squeeze1x1_fire2-relu_squeeze1x1_Bias' } {'fire2-relu_squeeze1x1'} "Bias" -0.11641 0.24273
{'fire2-expand1x1_fire2-relu_expand1x1_Weights' } {'fire2-relu_expand1x1' } "Weights" -0.7406 0.90982
{'fire2-expand1x1_fire2-relu_expand1x1_Bias' } {'fire2-relu_expand1x1' } "Bias" -0.060056 0.14602
{'fire2-expand3x3_fire2-relu_expand3x3_Weights' } {'fire2-relu_expand3x3' } "Weights" -0.74397 0.66905
{'fire2-expand3x3_fire2-relu_expand3x3_Bias' } {'fire2-relu_expand3x3' } "Bias" -0.051778 0.074239
{'fire3-squeeze1x1_fire3-relu_squeeze1x1_Weights'} {'fire3-relu_squeeze1x1'} "Weights" -0.77263 0.68897
{'fire3-squeeze1x1_fire3-relu_squeeze1x1_Bias' } {'fire3-relu_squeeze1x1'} "Bias" -0.10141 0.32678
{'fire3-expand1x1_fire3-relu_expand1x1_Weights' } {'fire3-relu_expand1x1' } "Weights" -0.72131 0.97287
{'fire3-expand1x1_fire3-relu_expand1x1_Bias' } {'fire3-relu_expand1x1' } "Bias" -0.067043 0.30424
{'fire3-expand3x3_fire3-relu_expand3x3_Weights' } {'fire3-relu_expand3x3' } "Weights" -0.61196 0.77431
{'fire3-expand3x3_fire3-relu_expand3x3_Bias' } {'fire3-relu_expand3x3' } "Bias" -0.053612 0.10329
{'fire4-squeeze1x1_fire4-relu_squeeze1x1_Weights'} {'fire4-relu_squeeze1x1'} "Weights" -0.74145 1.0888
{'fire4-squeeze1x1_fire4-relu_squeeze1x1_Bias' } {'fire4-relu_squeeze1x1'} "Bias" -0.10886 0.13882
...Use the validate function to quantize the learnable parameters in
the convolution layers of the network and exercise the network. The function uses
the metric function defined in the dlquantizationOptions object to
compare the results of the network before and after quantization.
valResults = validate(quantObj, aug_valData, quantOpts)
valResults =
struct with fields:
NumSamples: 20
MetricResults: [1x1 struct]Examine the MetricResults.Result field of the validation output
to see the performance of the quantized network.
valResults.MetricResults.Result
ans =
2x3 table
NetworkImplementation MetricOutput LearnableParameterMemory(bytes)
_____________________ ____________ _______________________________
{'Floating-Point'} 1 2.9003e+06
{'Quantized' } 1 7.3393e+05
In this example, the memory required for the network was reduced approximately 75% through quantization. The accuracy of the network is not affected.
The weights, biases, and activations of the convolution layers of the network
specified in the dlquantizer object now use scaled 8-bit integer
data types.
This example shows how to quantize learnable parameters in the
convolution layers of a neural network, and explore the behavior of the quantized
network. In this example, you quantize the LogoNet neural network.
Quantization helps reduce the memory requirement of a deep neural network by quantizing
weights, biases and activations of network layers to 8-bit scaled integer data types.
Use MATLAB® to retrieve the prediction results from the target device.
To run this example, you need the products listed under FPGA in
Quantization Workflow Prerequisites.
For additional requirements, see Quantization Workflow Prerequisites.
Create a file in your current working directory called
getLogoNetwork.m. Enter these lines into the file:
function net = getLogoNetwork() data = getLogoData(); net = data.convnet; end function data = getLogoData() if ~isfile('LogoNet.mat') url = 'https://www.mathworks.com/supportfiles/gpucoder/cnn_models/logo_detection/LogoNet.mat'; websave('LogoNet.mat',url); end data = load('LogoNet.mat'); end
Load the pretrained network.
snet = getLogoNetwork();
snet =
SeriesNetwork with properties:
Layers: [22×1 nnet.cnn.layer.Layer]
InputNames: {'imageinput'}
OutputNames: {'classoutput'}Define calibration and validation data to use for quantization.
The calibration data is used to collect the dynamic ranges of the weights and biases in the convolution and fully connected layers of the network and the dynamic ranges of the activations in all layers of the network. For the best quantization results, the calibration data must be representative of inputs to the network.
The validation data is used to test the network after quantization to understand the effects of the limited range and precision of the quantized convolution layers in the network.
This example uses the images in the logos_dataset data set.
Define an augmentedImageDatastore object to resize the data for the
network. Then, split the data into calibration and validation data sets.
curDir = pwd; newDir = fullfile(matlabroot,'examples','deeplearning_shared','data','logos_dataset.zip'); copyfile(newDir,curDir); unzip('logos_dataset.zip'); imageData = imageDatastore(fullfile(curDir,'logos_dataset'),... 'IncludeSubfolders',true,'FileExtensions','.JPG','LabelSource','foldernames'); [calibrationData, validationData] = splitEachLabel(imageData, 0.5,'randomized');
Create a dlquantizer object and specify the network to
quantize.
dlQuantObj = dlquantizer(snet,'ExecutionEnvironment','FPGA');
Use the calibrate function to exercise the network with sample
inputs and collect range information. The calibrate function
exercises the network and collects the dynamic ranges of the weights and biases in
the convolution and fully connected layers of the network and the dynamic ranges of
the activations in all layers of the network. The function returns a table. Each row
of the table contains range information for a learnable parameter of the optimized
network.
dlQuantObj.calibrate(calibrationData)
ans =
Optimized Layer Name Network Layer Name Learnables / Activations MinValue MaxValue
____________________________ __________________ ________________________ ___________ __________
{'conv_1_Weights' } {'conv_1' } "Weights" -0.048978 0.039352
{'conv_1_Bias' } {'conv_1' } "Bias" 0.99996 1.0028
{'conv_2_Weights' } {'conv_2' } "Weights" -0.055518 0.061901
{'conv_2_Bias' } {'conv_2' } "Bias" -0.00061171 0.00227
{'conv_3_Weights' } {'conv_3' } "Weights" -0.045942 0.046927
{'conv_3_Bias' } {'conv_3' } "Bias" -0.0013998 0.0015218
{'conv_4_Weights' } {'conv_4' } "Weights" -0.045967 0.051
{'conv_4_Bias' } {'conv_4' } "Bias" -0.00164 0.0037892
{'fc_1_Weights' } {'fc_1' } "Weights" -0.051394 0.054344
{'fc_1_Bias' } {'fc_1' } "Bias" -0.00052319 0.00084454
{'fc_2_Weights' } {'fc_2' } "Weights" -0.05016 0.051557
{'fc_2_Bias' } {'fc_2' } "Bias" -0.0017564 0.0018502
{'fc_3_Weights' } {'fc_3' } "Weights" -0.050706 0.04678
{'fc_3_Bias' } {'fc_3' } "Bias" -0.02951 0.024855
{'imageinput' } {'imageinput'} "Activations" 0 255
{'imageinput_normalization'} {'imageinput'} "Activations" -139.34 198.72
Create a target object with a custom name for your target device and an interface to connect your target device to the host computer. Interface options are JTAG and Ethernet. To create the target object, enter:
hTarget = dlhdl.Target('Intel', 'Interface', 'JTAG');
Define a metric function to use to compare the behavior of the network before and after quantization. Save this function in a local file.
function accuracy = hComputeAccuracy(predictionScores, net, dataStore) %% hComputeAccuracy test helper function computes model level accuracy statistics % Copyright 2020 The MathWorks, Inc. % Load ground truth groundTruth = dataStore.Labels; % Compare with predicted label with actual ground truth predictionError = {}; for idx=1:numel(groundTruth) [~, idy] = max(predictionScores(idx, :)); yActual = net.Layers(end).Classes(idy); predictionError{end+1} = (yActual == groundTruth(idx)); %#ok end % Sum all prediction errors. predictionError = [predictionError{:}]; accuracy = sum(predictionError)/numel(predictionError); end
Specify the metric function in a dlquantizationOptions
object.
options = dlquantizationOptions('MetricFcn', ... {@(x)hComputeModelAccuracy(x, snet, validationData)},'Bitstream','arria10soc_int8',... 'Target',hTarget);
To compile and deploy the quantized network, run the validate
function of the dlquantizer object. Use the
validate function to quantize the learnable parameters in the
convolution layers of the network and exercise the network. This function uses the
output of the compile function to program the FPGA board by using the programming
file. It also downloads the network weights and biases. The deploy function checks
for the Intel Quartus tool and the supported tool version. It then starts
programming the FPGA device by using the sof file, displays progress messages, and
the time it takes to deploy the network. The function uses the metric function
defined in the dlquantizationOptions object to compare the results
of the network before and after quantization.
prediction = dlQuantObj.validate(validationData,options);
offset_name offset_address allocated_space
_______________________ ______________ _________________
"InputDataOffset" "0x00000000" "48.0 MB"
"OutputResultOffset" "0x03000000" "4.0 MB"
"SystemBufferOffset" "0x03400000" "60.0 MB"
"InstructionDataOffset" "0x07000000" "8.0 MB"
"ConvWeightDataOffset" "0x07800000" "8.0 MB"
"FCWeightDataOffset" "0x08000000" "12.0 MB"
"EndOffset" "0x08c00000" "Total: 140.0 MB"
### Programming FPGA Bitstream using JTAG...
### Programming the FPGA bitstream has been completed successfully.
### Loading weights to Conv Processor.
### Conv Weights loaded. Current time is 16-Jul-2020 12:45:10
### Loading weights to FC Processor.
### FC Weights loaded. Current time is 16-Jul-2020 12:45:26
### Finished writing input activations.
### Running single input activations.
Deep Learning Processor Profiler Performance Results
LastLayerLatency(cycles) LastLayerLatency(seconds) FramesNum Total Latency Frames/s
------------- ------------- --------- --------- ---------
Network 13570959 0.09047 30 380609145 11.8
conv_module 12667786 0.08445
conv_1 3938907 0.02626
maxpool_1 1544560 0.01030
conv_2 2910954 0.01941
maxpool_2 577524 0.00385
conv_3 2552707 0.01702
maxpool_3 676542 0.00451
conv_4 455434 0.00304
maxpool_4 11251 0.00008
fc_module 903173 0.00602
fc_1 536164 0.00357
fc_2 342643 0.00228
fc_3 24364 0.00016
* The clock frequency of the DL processor is: 150MHz
### Finished writing input activations.
### Running single input activations.
Deep Learning Processor Profiler Performance Results
LastLayerLatency(cycles) LastLayerLatency(seconds) FramesNum Total Latency Frames/s
------------- ------------- --------- --------- ---------
Network 13570364 0.09047 30 380612682 11.8
conv_module 12667103 0.08445
conv_1 3939296 0.02626
maxpool_1 1544371 0.01030
conv_2 2910747 0.01940
maxpool_2 577654 0.00385
conv_3 2551829 0.01701
maxpool_3 676548 0.00451
conv_4 455396 0.00304
maxpool_4 11355 0.00008
fc_module 903261 0.00602
fc_1 536206 0.00357
fc_2 342688 0.00228
fc_3 24365 0.00016
* The clock frequency of the DL processor is: 150MHz
### Finished writing input activations.
### Running single input activations.
Deep Learning Processor Profiler Performance Results
LastLayerLatency(cycles) LastLayerLatency(seconds) FramesNum Total Latency Frames/s
------------- ------------- --------- --------- ---------
Network 13571561 0.09048 30 380608338 11.8
conv_module 12668340 0.08446
conv_1 3939070 0.02626
maxpool_1 1545327 0.01030
conv_2 2911061 0.01941
maxpool_2 577557 0.00385
conv_3 2552082 0.01701
maxpool_3 676506 0.00451
conv_4 455582 0.00304
maxpool_4 11248 0.00007
fc_module 903221 0.00602
fc_1 536167 0.00357
fc_2 342643 0.00228
fc_3 24409 0.00016
* The clock frequency of the DL processor is: 150MHz
### Finished writing input activations.
### Running single input activations.
Deep Learning Processor Profiler Performance Results
LastLayerLatency(cycles) LastLayerLatency(seconds) FramesNum Total Latency Frames/s
------------- ------------- --------- --------- ---------
Network 13569862 0.09047 30 380613327 11.8
conv_module 12666756 0.08445
conv_1 3939212 0.02626
maxpool_1 1543267 0.01029
conv_2 2911184 0.01941
maxpool_2 577275 0.00385
conv_3 2552868 0.01702
maxpool_3 676438 0.00451
conv_4 455353 0.00304
maxpool_4 11252 0.00008
fc_module 903106 0.00602
fc_1 536050 0.00357
fc_2 342645 0.00228
fc_3 24409 0.00016
* The clock frequency of the DL processor is: 150MHz
### Finished writing input activations.
### Running single input activations.
Deep Learning Processor Profiler Performance Results
LastLayerLatency(cycles) LastLayerLatency(seconds) FramesNum Total Latency Frames/s
------------- ------------- --------- --------- ---------
Network 13570823 0.09047 30 380619836 11.8
conv_module 12667607 0.08445
conv_1 3939074 0.02626
maxpool_1 1544519 0.01030
conv_2 2910636 0.01940
maxpool_2 577769 0.00385
conv_3 2551800 0.01701
maxpool_3 676795 0.00451
conv_4 455859 0.00304
maxpool_4 11248 0.00007
fc_module 903216 0.00602
fc_1 536165 0.00357
fc_2 342643 0.00228
fc_3 24406 0.00016
* The clock frequency of the DL processor is: 150MHz
offset_name offset_address allocated_space
_______________________ ______________ _________________
"InputDataOffset" "0x00000000" "48.0 MB"
"OutputResultOffset" "0x03000000" "4.0 MB"
"SystemBufferOffset" "0x03400000" "60.0 MB"
"InstructionDataOffset" "0x07000000" "8.0 MB"
"ConvWeightDataOffset" "0x07800000" "8.0 MB"
"FCWeightDataOffset" "0x08000000" "12.0 MB"
"EndOffset" "0x08c00000" "Total: 140.0 MB"
### FPGA bitstream programming has been skipped as the same bitstream is already loaded on the target FPGA.
### Deep learning network programming has been skipped as the same network is already loaded on the target FPGA.
### Finished writing input activations.
### Running single input activations.
Deep Learning Processor Profiler Performance Results
LastLayerLatency(cycles) LastLayerLatency(seconds) FramesNum Total Latency Frames/s
------------- ------------- --------- --------- ---------
Network 13572329 0.09048 10 127265075 11.8
conv_module 12669135 0.08446
conv_1 3939559 0.02626
maxpool_1 1545378 0.01030
conv_2 2911243 0.01941
maxpool_2 577422 0.00385
conv_3 2552064 0.01701
maxpool_3 676678 0.00451
conv_4 455657 0.00304
maxpool_4 11227 0.00007
fc_module 903194 0.00602
fc_1 536140 0.00357
fc_2 342688 0.00228
fc_3 24364 0.00016
* The clock frequency of the DL processor is: 150MHz
### Finished writing input activations.
### Running single input activations.
Deep Learning Processor Profiler Performance Results
LastLayerLatency(cycles) LastLayerLatency(seconds) FramesNum Total Latency Frames/s
------------- ------------- --------- --------- ---------
Network 13572527 0.09048 10 127266427 11.8
conv_module 12669266 0.08446
conv_1 3939776 0.02627
maxpool_1 1545632 0.01030
conv_2 2911169 0.01941
maxpool_2 577592 0.00385
conv_3 2551613 0.01701
maxpool_3 676811 0.00451
conv_4 455418 0.00304
maxpool_4 11348 0.00008
fc_module 903261 0.00602
fc_1 536205 0.00357
fc_2 342689 0.00228
fc_3 24365 0.00016
* The clock frequency of the DL processor is: 150MHzExamine the MetricResults.Result field of the validation output
to see the performance of the quantized network.
validateOut = prediction.MetricResults.Result
ans =
NetworkImplementation MetricOutput
_____________________ ____________
{'Floating-Point'} 0.9875
{'Quantized' } 0.9875
Examine the QuantizedNetworkFPS field of the validation output
to see the frames per second performance of the quantized network.
prediction.QuantizedNetworkFPS
ans = 11.8126
The weights, biases, and activations of the convolution layers of the network
specified in the dlquantizer object now use scaled 8-bit integer
data types.