libsvm Shrinking Heuristics

Question

I\'m using libsvm in C-SVC mode with a polynomial kernel of degree 2 and I\'m required to train multiple SVMs. During training, I am getting either one or even both of these war

Answer 1

The shrinking heuristics are there to speed up the optimization. As it says in the FAQ, they sometimes help, and sometimes they do not. I believe it's a matter of runtime, rather than convergence.

The fact that the optimization reaches the maximum number of iterations is interesting, though. You might want to play with the tolerance (cost parameter), or have a look at the individual problems that cause this. Are the datasets large?