Which kernels do you know? How to choose a kernel?

Which kernels do you know? How to choose a kernel?



-Gaussian kernel
-Linear kernel
-Polynomial kernel
-Laplace kernel
-Esoteric kernels: string kernels, chi-square kernels
-If number of features is large (relative to number of observations): SVM with linear kernel ; e.g. text classification with lots of words, small training example
-If number of features is small, number of observations is intermediate: Gaussian kernel
-If number of features is small, number of observations is small: linear kernel

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