Parameter ranges for sigmoid and polynomial kernel

Hello

I would like to use a SVM classifier with a sigmoid and polynomial kernel.

The sigmoid kernel has the following form: tanh(gamma * u'*v + coef0)

The polynomial kernel has the following form: (gamma * u'*v + coef0)^degree

Which parameter ranges are resonable to try for gamma and coef0?

[John D'Errico]

You don't think that depends entirely upon your data? Let me rephrase that - it depends entirely upon your data. Knowing nothing at all about your specific problem & data, [-inf,inf] is virtually as much as one can say.