dlquantizationOptions

Options for quantizing a trained deep neural network

Since R2020a

Description

The dlquantizationOptions object provides options for quantizing a trained deep neural network to scaled 8-bit integer data types.

This object requires Deep Learning Toolbox Model Quantization Library. To learn about the products required to quantize a deep neural network, see Quantization Workflow Prerequisites.

Creation

Syntax

quantOpts = dlquantizationOptions

quantOpts = dlquantizationOptions(Name,Value)

Description

quantOpts = dlquantizationOptions creates a dlquantizationOptions object with default property values.

quantOpts = dlquantizationOptions(Name,Value) creates a dlquantizationOptions object with additional properties specified by one or more name-value pair arguments.

Properties

MetricFcn — Metric function to use for validation of quantized network

cell array of function handles

Metric function to use for validation of quantized network, specified as a cell array of one or more function handles.

Example: options = dlquantizationOptions('MetricFcn',{@(x)hComputeModelAccuracy(x,net,groundTruth)});

Data Types: cell

Execution Environment Options

Bitstream — Name of FPGA bitstream

'zcu102_int8' | 'zc706_int8' | 'arria10soc_int8'

This property is valid only when the 'ExecutionEnvironment property of the dlquantizer object is set to 'FPGA'.

Name of the FPGA bitstream specified, as one of these values:

Bitstream	Target Board
'zcu102_int8'	Xilinx® Zynq® UltraScale™ ZCU102
'zc706_int8'	Xilinx Zynq-7000 ZC706
'arria10soc_int8'	Intel® Arria® 10 SoC development kit

Example: quantOpts = dlquantizationOptions('Bitstream','zcu102_int8')

Target — Target for quantized network

dlhdl.Target object | raspi object

Target for quantized network, specified as one of the following:

Target	Execution Environment for Quantized Network	Example
Target CPU board specified as a raspi object	Set Target property as a raspi object only when 'ExecutionEnvironment property of the dlquantizer object is set to 'CPU'	r = raspi('hostname','User Name','Password'); quantOpts = dlquantizationOptions('Target',r)
Target FPGA board vendor name and interface, specified as a dlhdl.Target (Deep Learning HDL Toolbox) object	Set Target property as a dlhdl.Target object only when 'ExecutionEnvironment property of the dlquantizer object is set to 'FPGA'	hTarget = dlhdl.Target('Intel','Interface','JTAG'); quantOpts = dlquantizationOptions('Target',hTarget)

Examples

Quantize a Neural Network for GPU Target

This example shows how to quantize learnable parameters in the convolution layers of a neural network for GPU 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 is the output network of the Train Deep Learning Network to Classify New Images example.

load squeezenetmerch
net

net = 
  DAGNetwork with properties:

         Layers: [68×1 nnet.cnn.layer.Layer]
    Connections: [75×2 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. This example uses the hComputeModelAccuracy metric function.

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=121×5 table
        Optimized Layer Name         Network Layer Name     Learnables / Activations    MinValue     MaxValue
    ____________________________    ____________________    ________________________    _________    ________

    {'conv1_Weights'           }    {'conv1'           }           "Weights"             -0.91985     0.88489
    {'conv1_Bias'              }    {'conv1'           }           "Bias"                -0.07925     0.26343
    {'fire2-squeeze1x1_Weights'}    {'fire2-squeeze1x1'}           "Weights"                -1.38      1.2477
    {'fire2-squeeze1x1_Bias'   }    {'fire2-squeeze1x1'}           "Bias"                -0.11641     0.24273
    {'fire2-expand1x1_Weights' }    {'fire2-expand1x1' }           "Weights"              -0.7406     0.90982
    {'fire2-expand1x1_Bias'    }    {'fire2-expand1x1' }           "Bias"               -0.060056     0.14602
    {'fire2-expand3x3_Weights' }    {'fire2-expand3x3' }           "Weights"             -0.74397     0.66905
    {'fire2-expand3x3_Bias'    }    {'fire2-expand3x3' }           "Bias"               -0.051778    0.074239
    {'fire3-squeeze1x1_Weights'}    {'fire3-squeeze1x1'}           "Weights"              -0.7712     0.68917
    {'fire3-squeeze1x1_Bias'   }    {'fire3-squeeze1x1'}           "Bias"                -0.10138     0.32675
    {'fire3-expand1x1_Weights' }    {'fire3-expand1x1' }           "Weights"             -0.72035      0.9743
    {'fire3-expand1x1_Bias'    }    {'fire3-expand1x1' }           "Bias"               -0.067029     0.30425
    {'fire3-expand3x3_Weights' }    {'fire3-expand3x3' }           "Weights"             -0.61443      0.7741
    {'fire3-expand3x3_Bias'    }    {'fire3-expand3x3' }           "Bias"               -0.053613     0.10329
    {'fire4-squeeze1x1_Weights'}    {'fire4-squeeze1x1'}           "Weights"              -0.7422      1.0877
    {'fire4-squeeze1x1_Bias'   }    {'fire4-squeeze1x1'}           "Bias"                -0.10885     0.13881
      ⋮

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: [1×1 struct]
       Statistics: [2×2 table]

Examine the validation output to see the performance of the quantized network.

valResults.MetricResults.Result

ans=2×2 table
    NetworkImplementation    MetricOutput
    _____________________    ____________

     {'Floating-Point'}           1      
     {'Quantized'     }           1      

valResults.Statistics

ans=2×2 table
    NetworkImplementation    LearnableParameterMemory(bytes)
    _____________________    _______________________________

     {'Floating-Point'}                2.9003e+06           
     {'Quantized'     }                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.

Quantize Network for FPGA Deployment

Reduce the memory footprint of a deep neural network by quantizing the weights, biases, and activations of convolution layers to 8-bit scaled integer data types. This example shows how to use Deep Learning Toolbox Model Quantization Library and Deep Learning HDL Toolbox to deploy the int8 network to a target FPGA board.

For this example, you need:

• Deep Learning Toolbox ™

• Deep Learning HDL Toolbox ™

• Deep Learning Toolbox Model Quantization Library

• Deep Learning HDL Toolbox Support Package for Xilinx FPGA and SoC Devices

• MATLAB Coder Interface for Deep Learning.

Load Pretrained Network

Load the pretrained LogoNet network and analyze the network architecture.

snet = getLogoNetwork;
deepNetworkDesigner(snet);

Load Data

This example uses the logos_dataset data set. The data set consists of 320 images. Each image is 227-by-227 in size and has three color channels (RGB). Create an augmentedImageDatastore object for calibration and validation. Expedite calibration and validation by reducing the calibration data set to 20 images. The MATLAB simulation workflow has a maximum limit of five images when validating the quantized network. Reduce the validation data set sizes to five images. The FPGA validation workflow has a maximum limit of one image when validating the quantized network. Reduce the FPGA validation data set to a single image.

curDir = pwd;
unzip("logos_dataset.zip");
imageData = imageDatastore(fullfile(curDir,'logos_dataset'),...
'IncludeSubfolders',true,'FileExtensions','.JPG','LabelSource','foldernames');
[calibrationData, validationData] = splitEachLabel(imageData, 0.5,'randomized');
calibrationData_reduced = calibrationData.subset(1:20);
validationData_simulation = validationData.subset(1:5);
validationData_FPGA = validationData.subset(1:1);

Generate Calibration Result File for the Network

Create a dlquantizer (Deep Learning HDL Toolbox) object and specify the network to quantize. Specify the execution environment as FPGA.

dlQuantObj_simulation = dlquantizer(snet,'ExecutionEnvironment',"FPGA",'Simulation','on');
dlQuantObj_FPGA = dlquantizer(snet,'ExecutionEnvironment',"FPGA");

Use the calibrate (Deep Learning HDL Toolbox) function to exercise the network with sample inputs and collect the range information. The calibrate function collects the dynamic ranges of the weights and biases. The calibrate function returns a table. Each row of the table contains range information for a learnable parameter of the quantized network.

calibrate(dlQuantObj_simulation,calibrationData_reduced)

ans=35×5 table
        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        193.72
      ⋮

calibrate(dlQuantObj_FPGA,calibrationData_reduced)

ans=35×5 table
        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        193.72
      ⋮

Create Target Object

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 use JTAG, install Xilinx™ Vivado™ Design Suite 2020.2. To set the Xilinx Vivado toolpath, enter:

% hdlsetuptoolpath('ToolName', 'Xilinx Vivado', 'ToolPath', 'C:\Xilinx\Vivado\2020.2\bin\vivado.bat');

To create the target object, enter:

hTarget = dlhdl.Target('Xilinx','Interface','Ethernet');

Alternatively, you can also use the JTAG interface.

% hTarget = dlhdl.Target('Xilinx', 'Interface', 'JTAG');

Create dlQuantizationOptions Object

Create a dlquantizationOptions object. Specify the target bitstream and target board interface. The default metric function is a Top-1 accuracy metric function.

options_FPGA = dlquantizationOptions('Bitstream','zcu102_int8','Target',hTarget);
options_simulation = dlquantizationOptions;

To use a custom metric function, specify the metric function in the dlquantizationOptions object.

options_FPGA = dlquantizationOptions('MetricFcn',{@(x)hComputeAccuracy(x,snet,validationData_FPGA)},'Bitstream','zcu102_int8','Target',hTarget);
options_simulation = dlquantizationOptions('MetricFcn',{@(x)hComputeAccuracy(x,snet,validationData_simulation)})

Validate Quantized Network

Use the validate function to quantize the learnable parameters in the convolution layers of the network. The validate function simulates the quantized network in MATLAB. The validate function uses the metric function defined in the dlquantizationOptions object to compare the results of the single-data-type network object to the results of the quantized network object.

prediction_simulation = dlQuantObj_simulation.validate(validationData_simulation,options_simulation)

Compiling leg: conv_1>>relu_4 ...
Compiling leg: conv_1>>relu_4 ... complete.
Compiling leg: maxpool_4 ...
Compiling leg: maxpool_4 ... complete.
Compiling leg: fc_1>>fc_3 ...
Compiling leg: fc_1>>fc_3 ... complete.

prediction_simulation = struct with fields:
       NumSamples: 5
    MetricResults: [1×1 struct]
       Statistics: []

For validation on an FPGA, the validate function:

• Programs the FPGA board by using the output of the compile method and the programming file

• Downloads the network weights and biases

• Compares the performance of the network before and after quantization

prediction_FPGA = dlQuantObj_FPGA.validate(validationData_FPGA,options_FPGA)

### Compiling network for Deep Learning FPGA prototyping ...
### Targeting FPGA bitstream zcu102_int8.
### The network includes the following layers:
     1   'imageinput'    Image Input             227×227×3 images with 'zerocenter' normalization and 'randfliplr' augmentations  (SW Layer)
     2   'conv_1'        Convolution             96 5×5×3 convolutions with stride [1  1] and padding [0  0  0  0]                (HW Layer)
     3   'relu_1'        ReLU                    ReLU                                                                             (HW Layer)
     4   'maxpool_1'     Max Pooling             3×3 max pooling with stride [2  2] and padding [0  0  0  0]                      (HW Layer)
     5   'conv_2'        Convolution             128 3×3×96 convolutions with stride [1  1] and padding [0  0  0  0]              (HW Layer)
     6   'relu_2'        ReLU                    ReLU                                                                             (HW Layer)
     7   'maxpool_2'     Max Pooling             3×3 max pooling with stride [2  2] and padding [0  0  0  0]                      (HW Layer)
     8   'conv_3'        Convolution             384 3×3×128 convolutions with stride [1  1] and padding [0  0  0  0]             (HW Layer)
     9   'relu_3'        ReLU                    ReLU                                                                             (HW Layer)
    10   'maxpool_3'     Max Pooling             3×3 max pooling with stride [2  2] and padding [0  0  0  0]                      (HW Layer)
    11   'conv_4'        Convolution             128 3×3×384 convolutions with stride [2  2] and padding [0  0  0  0]             (HW Layer)
    12   'relu_4'        ReLU                    ReLU                                                                             (HW Layer)
    13   'maxpool_4'     Max Pooling             3×3 max pooling with stride [2  2] and padding [0  0  0  0]                      (HW Layer)
    14   'fc_1'          Fully Connected         2048 fully connected layer                                                       (HW Layer)
    15   'relu_5'        ReLU                    ReLU                                                                             (HW Layer)
    16   'dropout_1'     Dropout                 50% dropout                                                                      (HW Layer)
    17   'fc_2'          Fully Connected         2048 fully connected layer                                                       (HW Layer)
    18   'relu_6'        ReLU                    ReLU                                                                             (HW Layer)
    19   'dropout_2'     Dropout                 50% dropout                                                                      (HW Layer)
    20   'fc_3'          Fully Connected         32 fully connected layer                                                         (HW Layer)
    21   'softmax'       Softmax                 softmax                                                                          (HW Layer)
    22   'classoutput'   Classification Output   crossentropyex with 'adidas' and 31 other classes                                (SW Layer)
                                                                                                                                
### Notice: The layer 'imageinput' with type 'nnet.cnn.layer.ImageInputLayer' is implemented in software.
### Notice: The layer 'softmax' with type 'nnet.cnn.layer.SoftmaxLayer' is implemented in software.
### Notice: The layer 'classoutput' with type 'nnet.cnn.layer.ClassificationOutputLayer' is implemented in software.
### Compiling layer group: conv_1>>relu_4 ...
### Compiling layer group: conv_1>>relu_4 ... complete.
### Compiling layer group: maxpool_4 ...
### Compiling layer group: maxpool_4 ... complete.
### Compiling layer group: fc_1>>fc_3 ...
### Compiling layer group: fc_1>>fc_3 ... complete.

### Allocating external memory buffers:

          offset_name          offset_address    allocated_space 
    _______________________    ______________    ________________

    "InputDataOffset"           "0x00000000"     "12.0 MB"       
    "OutputResultOffset"        "0x00c00000"     "4.0 MB"        
    "SchedulerDataOffset"       "0x01000000"     "4.0 MB"        
    "SystemBufferOffset"        "0x01400000"     "36.0 MB"       
    "InstructionDataOffset"     "0x03800000"     "8.0 MB"        
    "ConvWeightDataOffset"      "0x04000000"     "12.0 MB"       
    "FCWeightDataOffset"        "0x04c00000"     "12.0 MB"       
    "EndOffset"                 "0x05800000"     "Total: 88.0 MB"

### Network compilation complete.

### 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 activation.


              Deep Learning Processor Bitstream Build Info

Resource                   Utilized           Total        Percentage
------------------        ----------      ------------    ------------
LUTs (CLB/ALM)*              248358            274080           90.62
DSPs                            384              2520           15.24
Block RAM                       581               912           63.71
* LUT count represents Configurable Logic Block(CLB) utilization in Xilinx devices and Adaptive Logic Module (ALM) utilization in Intel devices.

### Notice: The layer 'imageinput' of type 'ImageInputLayer' is split into an image input layer 'imageinput' and an addition layer 'imageinput_norm' for normalization on hardware.
### Notice: The layer 'softmax' with type 'nnet.cnn.layer.SoftmaxLayer' is implemented in software.
### Notice: The layer 'classoutput' with type 'nnet.cnn.layer.ClassificationOutputLayer' is implemented in software.


              Deep Learning Processor Estimator Performance Results

                   LastFrameLatency(cycles)   LastFrameLatency(seconds)       FramesNum      Total Latency     Frames/s
                         -------------             -------------              ---------        ---------       ---------
Network                   40142478                  0.18247                       1           40142478              5.5
    ____imageinput_norm     216472                  0.00098 
    ____conv_1             6825671                  0.03103 
    ____maxpool_1          3755088                  0.01707 
    ____conv_2            10440701                  0.04746 
    ____maxpool_2          1447840                  0.00658 
    ____conv_3             9405685                  0.04275 
    ____maxpool_3          1765856                  0.00803 
    ____conv_4             1819636                  0.00827 
    ____maxpool_4            28098                  0.00013 
    ____fc_1               2651288                  0.01205 
    ____fc_2               1696632                  0.00771 
    ____fc_3                 89511                  0.00041 
 * The clock frequency of the DL processor is: 220MHz




              Deep Learning Processor Bitstream Build Info

Resource                   Utilized           Total        Percentage
------------------        ----------      ------------    ------------
LUTs (CLB/ALM)*              168645            274080           61.53
DSPs                            800              2520           31.75
Block RAM                       453               912           49.67
* LUT count represents Configurable Logic Block(CLB) utilization in Xilinx devices and Adaptive Logic Module (ALM) utilization in Intel devices.

### Finished writing input activations.
### Running single input activation.

prediction_FPGA = struct with fields:
       NumSamples: 1
    MetricResults: [1×1 struct]
       Statistics: [2×7 table]

View Performance of Quantized Neural Network

Display the accuracy of the quantized network.

prediction_simulation.MetricResults.Result

ans=2×2 table
    NetworkImplementation    MetricOutput
    _____________________    ____________

     {'Floating-Point'}           1      
     {'Quantized'     }           1      

prediction_FPGA.MetricResults.Result

ans=2×2 table
    NetworkImplementation    MetricOutput
    _____________________    ____________

     {'Floating-Point'}           1      
     {'Quantized'     }           1      

Display the performance of the quantized network in frames per second.

prediction_FPGA.Statistics.FramesPerSecond(2)

ans = 19.0828

Quantize a Neural Network for CPU Target

This example shows how to quantize and validate a neural network for a CPU target. This workflow is similar to other execution environments, but before validating you must establish a raspi connection and specify it as target using dlquantizationOptions.

First, load your network. This example uses the pretrained network squeezenet.

load squeezenetmerch
net

net = 
  DAGNetwork with properties:

         Layers: [68×1 nnet.cnn.layer.Layer]
    Connections: [75×2 table]
     InputNames: {'data'}
    OutputNames: {'new_classoutput'}

Then define your calibration and validation data, calDS and valDS respectively.

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 the dlquantizer object and specify a CPU execution environment.

dq =  dlquantizer(net,'ExecutionEnvironment','CPU') 

dq = 
  dlquantizer with properties:

           NetworkObject: [1×1 DAGNetwork]
    ExecutionEnvironment: 'CPU'

Calibrate the network.

calResults = calibrate(dq,aug_calData,'UseGPU','off')

calResults=122×5 table
        Optimized Layer Name         Network Layer Name     Learnables / Activations    MinValue     MaxValue
    ____________________________    ____________________    ________________________    _________    ________

    {'conv1_Weights'           }    {'conv1'           }           "Weights"             -0.91985     0.88489
    {'conv1_Bias'              }    {'conv1'           }           "Bias"                -0.07925     0.26343
    {'fire2-squeeze1x1_Weights'}    {'fire2-squeeze1x1'}           "Weights"                -1.38      1.2477
    {'fire2-squeeze1x1_Bias'   }    {'fire2-squeeze1x1'}           "Bias"                -0.11641     0.24273
    {'fire2-expand1x1_Weights' }    {'fire2-expand1x1' }           "Weights"              -0.7406     0.90982
    {'fire2-expand1x1_Bias'    }    {'fire2-expand1x1' }           "Bias"               -0.060056     0.14602
    {'fire2-expand3x3_Weights' }    {'fire2-expand3x3' }           "Weights"             -0.74397     0.66905
    {'fire2-expand3x3_Bias'    }    {'fire2-expand3x3' }           "Bias"               -0.051778    0.074239
    {'fire3-squeeze1x1_Weights'}    {'fire3-squeeze1x1'}           "Weights"              -0.7712     0.68917
    {'fire3-squeeze1x1_Bias'   }    {'fire3-squeeze1x1'}           "Bias"                -0.10138     0.32675
    {'fire3-expand1x1_Weights' }    {'fire3-expand1x1' }           "Weights"             -0.72035      0.9743
    {'fire3-expand1x1_Bias'    }    {'fire3-expand1x1' }           "Bias"               -0.067029     0.30425
    {'fire3-expand3x3_Weights' }    {'fire3-expand3x3' }           "Weights"             -0.61443      0.7741
    {'fire3-expand3x3_Bias'    }    {'fire3-expand3x3' }           "Bias"               -0.053613     0.10329
    {'fire4-squeeze1x1_Weights'}    {'fire4-squeeze1x1'}           "Weights"              -0.7422      1.0877
    {'fire4-squeeze1x1_Bias'   }    {'fire4-squeeze1x1'}           "Bias"                -0.10885     0.13881
      ⋮

Use the MATLAB Support Package for Raspberry Pi Hardware function, raspi, to create a connection to the Raspberry Pi. In the following code, replace:

• raspiname with the name or address of your Raspberry Pi

• username with your user name

• password with your password

% r = raspi('raspiname','username','password')

For example,

r = raspi('gpucoder-raspberrypi-7','pi','matlab')

r = 
  raspi with properties:

         DeviceAddress: 'gpucoder-raspberrypi-7'      
                  Port: 18734                         
             BoardName: 'Raspberry Pi 3 Model B+'     
         AvailableLEDs: {'led0'}                      
  AvailableDigitalPins: [2,3,4,5,6,7,8,9,10,11,12,13,14,15,16,17,18,19,20,21,22,23,24,25,26,27]
  AvailableSPIChannels: {}                            
     AvailableI2CBuses: {}                            
      AvailableWebcams: {}                            
           I2CBusSpeed:                               
AvailableCANInterfaces: {}                            

  Supported peripherals

Specify raspi object as the target for the quantized network.

opts = dlquantizationOptions('Target',r)

opts = 
  dlquantizationOptions with properties:

    MetricFcn: {}
    Bitstream: ''
       Target: [1×1 raspi]

Validate the quantized network with the validate function.

valResults = validate(dq,aug_valData,opts)

### Starting application: 'codegen\lib\validate_predict_int8\pil\validate_predict_int8.elf'
    To terminate execution: clear validate_predict_int8_pil
### Launching application validate_predict_int8.elf...
### Host application produced the following standard output (stdout) and standard error (stderr) messages:

valResults = struct with fields:
       NumSamples: 20
    MetricResults: [1×1 struct]
       Statistics: []

Examine the validation output to see the performance of the quantized network.

valResults.MetricResults.Result

ans=2×2 table
    NetworkImplementation    MetricOutput
    _____________________    ____________

     {'Floating-Point'}          0.95    
     {'Quantized'     }          0.95    

Version History

Introduced in R2020a

R2023a: Specify Raspberry Pi as quantization target

You can now specify a raspi object as the target for quantization using the Target property when dlquantizer Execution Environment is set to CPU.