strange results with polynomial kernel

[vaskonov]

Hello,

For some reason I get very strange classifications with polynomial kernel. I have 966 training instances and 518 test instances. With polynomial kernel I have only negative classifications. With any other kernel I have different results with small variance (accuracy is approximately 35%).

The problem is I don't understand why polynomial kernel gives these non-meaningful results. How I can debug it?

[mricherzhagen]

Did you do a grid search to find the optimal kernel parameters?