does matlab 2015 support svm multiclass??

I use matlab 2013b for programmation but this version does not support svm multiclass. my question there is another version that support svm for multi classification?

Answer 1

[Walter Roberson]

Not directly. There is ClassificationECOC

"ClassificationECOC is an error-correcting output codes (ECOC) classifier for multiclass learning by reduction to multiple, binary classifiers such as support vector machines (SVMs). Train a ClassificationECOC classifier using fitcecoc and the training data."

Real multiclass SVM is really slow and needs a lot of memory, and is considered "feasible" (under a loose sense of the word) for at most 3 classes, and "possible if you are willing to wait several days" for 4 classes, but a matter for supercomputer clusters for 5 or more classes.

[Sahar abdalah]

thank you for your answer but this type of classification (ClassificationECOC)can handle a large number of classes ?? because I work on a database which contains 1000 classes and I want to know if it is possible to transform the output of SVMs into probability?

[Walter Roberson]

It looks to me as if it can handle a large number of classes, but the computation is going to involve a decision matrix which is potentially large; see <http://www.mathworks.com/help/stats/classificationecoc-class.html#bue4w15 Coding Design" for how many rows the matrix would have.

I have not investigated how to interpret the various kinds of decision outputs.