hi,
I was just wondering, what is the formula used for the RBF Kernel, is it the first or second (Gauss-RBF) formula used from here:
https://en.wikipedia.org/wiki/Radial_basis_function_kernel
because I noticed, when I set parameter Gamma, the training data will usually overfit if my gamma is chosen very small, but in other literatures, I read that if u make gamma big enough, the training point influence will get closer to each point, which means it overfits...
but I guess, as my data gets overfit if gamma is smaller, what actually is meant by gamma in the LibSVM Parameter is Sigma... and probably the formula: gamma = 1/(2*sigma^2) was used, is that correct?