我尝试使用Web Security Testing Cookbook: Systematic Techniques to Find Problems Fast优化机器学习参数。但是,由于单元格类型数据,我遇到了以下错误:
错误在KFold loss function
我尝试了以下代码:
% Make some data
Daten = rand(100, 3);
Daten(:,3) = Daten(:,1) + Daten(:,2) + .1*randn(100, 1); % Minimum asymptotic error is .1
[m,n] = size(Daten) ;
% Split into train and test
P = 0.7 ;
Training = Daten(1:round(P*m),:) ;
Testing = Daten(round(P*m)+1:end,:);
%%
XTr = Training(:,1:n-1);
YTr = Training(:,n);
XTe = Testing(:,1:n-1);
YTe = Testing(:,n);
XTrain=num2cell(XTr(:,1));
YTrain=num2cell(YTr(:,1));
XTest=num2cell(XTe);
YTest=num2cell(YTe);
% Define a train/validation split to use inside the objective function
cv = cvpartition(numel(YTrain), 'Holdout', 1/3);
% Define hyperparameters to optimize
vars = [optimizableVariable('hiddenLayerSize', [1,20], 'Type', 'integer');
optimizableVariable('lr', [1e-3 1], 'Transform', 'log')];
% Optimize
minfn = @(T)kfoldLoss(XTrain', YTrain', cv, T.hiddenLayerSize, T.lr);
results = bayesopt(minfn, vars,'IsObjectiveDeterministic', false,...
'AcquisitionFunctionName', 'expected-improvement-plus');
T = bestPoint(results)
-------------------------------------------------------------------
function rmse = kfoldLoss(x, y, cv, numHid, lr)
% Train net.
net = feedforwardnet(numHid, 'traingd');
net.trainParam.lr = lr;
net = train(net, x(:,cv.training), y(:,cv.training));
% Evaluate on validation set and compute rmse
ypred = net(x(:, cv.test));
rmse = sqrt(mean((ypred - y(cv.test)).^2));