Grouping variable must be a vector or a character array.

This is my code:

load classify_data

itr = 500;
hWaitBar = waitbar(0,'Image is still classifying...');
for i = 1:itr

data = train_feat;
groups = ismember(test_label,0);

[train,test] = crossvalind('HoldOut',groups);

svmStruct = svmtrain(data(train,:),groups(train),'showplot',false,'kernel_function','linear');

classes = svmclassify(svmStruct,data(test,:),'showplot',false);

end

Answer 1

[Walter Roberson]

All I can think of is that you might be generating only 0 or 1 train members, in which case groups(train) would be empty or a scalar.