AlexNet pretrained network?

hello

i have this code and i need to exchange AlexNet with (vgg16, vgg19, ResNet18 and densnet201) one by one.

could you please tell me which part of this code should be changed?

 clear all; close all; clc;
imds = imageDatastore('lung augmented', ...
    'IncludeSubfolders',true, ...
    'LabelSource','foldernames'); % for JPG images
[imdsTrain,imdsValidation] = splitEachLabel(imds,0.7,'randomize',true);

net = alexnet(); % analyzeNetwork(lgraph)

numClasses = numel(categories(imdsTrain.Labels)); % number of classes = number of folders
imageSize = [224 224]; % you can use here the original dataset size

lgraph = layerGraph(net.Layers);
lgraph = removeLayers(lgraph, 'fc8');
lgraph = removeLayers(lgraph, 'prob');
lgraph = removeLayers(lgraph, 'output');

% create and add layers
inputLayer = imageInputLayer([imageSize 1], 'Name', net.Layers(1).Name,...
    'DataAugmentation', net.Layers(1).DataAugmentation, ...
    'Normalization', net.Layers(1).Normalization);
lgraph = replaceLayer(lgraph,net.Layers(1).Name,inputLayer);
newConv1_Weights = net.Layers(2).Weights;
newConv1_Weights = mean(newConv1_Weights(:,:,1:3,:), 3); % taking the mean of kernal channels
newConv1 = convolution2dLayer(net.Layers(2).FilterSize(1), net.Layers(2).NumFilters,...
    'Name', net.Layers(2).Name,...
    'NumChannels', inputLayer.InputSize(3),...
    'Stride', net.Layers(2).Stride,...
    'DilationFactor', net.Layers(2).DilationFactor,...
    'Padding', net.Layers(2).PaddingSize,...
    'Weights', newConv1_Weights,...BiasLearnRateFactor 
    'Bias', net.Layers(2).Bias,...
    'BiasLearnRateFactor', net.Layers(2).BiasLearnRateFactor);
lgraph = replaceLayer(lgraph,net.Layers(2).Name,newConv1);
lgraph = addLayers(lgraph, fullyConnectedLayer(numClasses,'Name', 'fc2'));
lgraph = addLayers(lgraph, softmaxLayer('Name', 'softmax'));
lgraph = addLayers(lgraph, classificationLayer('Name','output'));
lgraph = connectLayers(lgraph, 'drop7', 'fc2');
lgraph = connectLayers(lgraph, 'fc2', 'softmax');
lgraph = connectLayers(lgraph, 'softmax', 'output');
% -------------------------------------------------------------------------
augimdsTrain = augmentedImageDatastore(imageSize,imdsTrain);
augimdsValidation = augmentedImageDatastore(imageSize,imdsValidation);

options = trainingOptions('sgdm', ...
    'MiniBatchSize',64, ...
    'MaxEpochs',30, ...  % i changed this from 20 to 10 and 5
    'InitialLearnRate',0.0001, ...
    'Shuffle','every-epoch', ...
    'ValidationData',augimdsValidation, ...
    'ValidationFrequency',3, ...
    'Verbose',false, ...
    'Plots','training-progress');
net = trainNetwork(augimdsTrain,lgraph,options)
[YPred, probs] = classify(net,augimdsValidation);
accuracy = mean(YPred ==imdsValidation.Labels)
figure
cc = confusionchart (imdsValidation.Labels, YPred);

[Walter Roberson]

I am not clear as to what you mean by "exchanging" those?

[shivan artosh]

i mean substitute alexnet with another network e.g. (vgg16, vgg19, densnet...) as shown in this line:

net = alexnet(); % analyzeNetwork(lgraph)

Answer 1

[Walter Roberson]

nets = {alexnet(), vgg16(), vgg19(), resnet18()};   %I do not see desnet201 available
numnet = length(nets);
for netidx = 1 : numnet
    net = nets{netidx};
    now do your stuff starting from the assignment to numClasses
end

I tend to suspect that the exact names of the existing layers to remove will differ from model to model.

[shivan artosh]

could please explain more

"I tend to suspect that the exact names of the existing layers to remove will differ from model to model."

for example which layers name will be changed ?

[Walter Roberson]

fc8

[shivan artosh]

AlexNet is 8 layers deep, VGG-16 is 16 layers deep, ResNet-18 is 18 layers deep and so on.

so, is it possible to change fc8 to fc16 ? or something else?

lgraph = removeLayers(lgraph, 'fc8');

to

lgraph = removeLayers(lgraph, 'fc16');

[Mohammad Sami]

Yes it should of there is a layer name fc16.

[shivan artosh]

my question is:

i want to substitute alexnet with (vgg16, vgg19, resnen ,...) separately.

so, how can i do that and how it will be? i mean exactly which part of code should i change? how?

[Walter Roberson]

nets = {alexnet(), vgg16(), vgg19(), resnet18()};   %I do not see desnet201 available
fc_layers = {'fc8', 'fc16', 'fc19', 'fc18'};
numnet = length(nets);
for netidx = 1 : numnet
    net = nets{netidx};
    now do your stuff starting from the assignment to numClasses
    lgraph = removeLayers(lgraph, fc_layers{netidx});
    and more stuff
end

[shivan artosh]

i use only resnet18, but i got this error:

Error using nnet.cnn.LayerGraph>iValidateLayerName (line 663)
Layer 'fc18' does not exist.

Error in nnet.cnn.LayerGraph/removeLayers (line 234)
                iValidateLayerName( ...

Error in SHIVANaugmented_test (line 20)
lgraph = removeLayers(lgraph, 'fc18');

[Walter Roberson]

It looks to me as if resnet18 has a layer 'fc1000'