Multi-Class SVM( one versus all)

Question

I know that LIBSVM only allows one-vs-one classification when it comes to multi-class SVM. However, I would like to tweak it a bit to perform one-against-all classification.

Answer 1

Instead of probability estimates, you can also use the decision values as follows

[~,~,d] = svmpredict(double(testLabel==k), testData, model{k});
prob(:,k) = d * (2 * model{i}.Label(1) - 1);

to achieve the same purpose.