Adding Cross Validation to Classification code
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I want to add cross validation (e.g. 10-fold) in my classification code. Every time it shall use 10 percents of data.
How can I do that
code:
clear all
close all
TrainRatio=0.8;
ValidationRatio=0.1;
folder='/Users/pooyan/Documents/normal/'; % change this path to your normal data folder
audio_files=dir(fullfile(folder,'*.ogg'));
nfileNum=length(audio_files);
%nfileNum=200
normal=[];
for i = 1:nfileNum
normal_name = [folder audio_files(i).name];
normal(i,:) = audioread(normal_name);
end
normal=normal';
nLabels = repelem(categorical("normal"),nfileNum,1);
folder='/Users/pooyan/Documents/anomaly/'; % change this path to your anomaly data folder
audio_files=dir(fullfile(folder,'*.ogg'));
afileNum=length(audio_files);
anomaly=[];
for i = 1:afileNum
anomaly_name = [folder audio_files(i).name];
anomaly(i,:) = audioread(anomaly_name);
end
anomaly=anomaly';
aLabels = repelem(categorical("anomaly"),afileNum,1);
% randomize the inputs if necessary
% normal=normal(:,randperm(nfileNum, nfileNum));
% anomaly=anomaly(:,randperm(afileNum, afileNum));
nTrainNum = round(nfileNum*TrainRatio);
aTrainNum = round(afileNum*TrainRatio);
nValidationNum = round(nfileNum*ValidationRatio);
aValidationNum = round(afileNum*ValidationRatio);
audioTrain = [normal(:,1:nTrainNum),anomaly(:,1:aTrainNum)];
labelsTrain = [nLabels(1:nTrainNum);aLabels(1:aTrainNum)];
audioValidation = [normal(:,nTrainNum+1:nTrainNum+nValidationNum),anomaly(:,aTrainNum+1:aTrainNum+aValidationNum)];
labelsValidation = [nLabels(nTrainNum+1:nTrainNum+nValidationNum);aLabels(aTrainNum+1:aTrainNum+aValidationNum)];
audioTest = [normal(:,nTrainNum+nValidationNum+1:end),anomaly(:,aTrainNum+aValidationNum+1:end)];
labelsTest = [nLabels(nTrainNum+nValidationNum+1:end); aLabels(aTrainNum+aValidationNum+1:end)];
fs=44100;
% Create an audioFeatureExtractor object
%to extract the centroid and slope of the mel spectrum over time.
aFE = audioFeatureExtractor("SampleRate",fs, ... %Fs
"SpectralDescriptorInput","melSpectrum", ...
"spectralCentroid",true, ...
"spectralSlope",true);
featuresTrain = extract(aFE,audioTrain);
[numHopsPerSequence,numFeatures,numSignals] = size(featuresTrain);
numHopsPerSequence;
numFeatures;
numSignals;
%treat the extracted features as sequences and use a
%sequenceInputLayer as the first layer of your deep learning model.
featuresTrain = permute(featuresTrain,[2,1,3]); %permute switching dimensions in array
featuresTrain = squeeze(num2cell(featuresTrain,[1,2]));%remove dimensions
numSignals = numel(featuresTrain); %number of signals of normal and anomalies
[numFeatures,numHopsPerSequence] = size(featuresTrain{1});
%Extract the validation features.
featuresValidation = extract(aFE,audioValidation);
featuresValidation = permute(featuresValidation,[2,1,3]);
featuresValidation = squeeze(num2cell(featuresValidation,[1,2]));
%Define the network architecture.
layers = [ ...
sequenceInputLayer(numFeatures)
lstmLayer(50,"OutputMode","last")
fullyConnectedLayer(numel(unique(labelsTrain))) %%labelTrain=audio
softmaxLayer
classificationLayer];
%To define the training options
options = trainingOptions("adam", ...
"Shuffle","every-epoch", ...
"ValidationData",{featuresValidation,labelsValidation}, ... %%labelValidatin=audioValidation
"Plots","training-progress", ...
"Verbose",false);
%To train the network
net = trainNetwork(featuresTrain,labelsTrain,layers,options);
%Test the network %10 preccent
%classify(net,permute(extract(aFE,audioTest),[2 257 35]))
TestFeature=extract(aFE, audioTest);
for i=1:size(TestFeature, 3)
TestFeatureIn = TestFeature(:,:,i)';
classify(net,TestFeatureIn)
end
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回答(1 个)
Aditya Patil
2020-11-16
编辑:Aditya Patil
2020-11-16
Currently, KFold validation is not supported for neural networks. I have brought the issue to the notice of the concerned people.
Note that KFold validation is not commonly used for neural networks, as neural networks are generally used with large amount of data, and hence KFold validation is not required.
You can split the dataset into 10 parts, and use different set of 9 parts each time to train the network, and validate on the remaining 1 part. You can do so using cvpartition and training functions. For example,
load fisheriris;
data_size = size(meas);
folds = 10;
c = cvpartition(data_size(1), "KFold", folds);
for i = 1:folds
idx = training(c, i);
train = meas(idx);
test = meas(~idx);
% train and test model here
end
However, if quantity of data is an issue, I would recommend using other machine learning techniques such as SVM or trees, as that might give you better results. You can use the classification learner app for this.
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