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Old 05-21-2012, 11:03 PM
sakumar sakumar is offline
Join Date: Apr 2012
Posts: 40
Default Re: What Quadratic Programming Package?

Originally Posted by kurts View Post
No, I never did check the info. I was pretty sure things were working right because I got a reasonable number of support vectors, and almost all the time when I calculated b, I got the same value with all the support vector alphas. However, once in a while, I would get different b values for a given set of alphas, but I just chose to ignore those.
I see something strange too, but I am not sure if you are referring to that.

What I see is that occasionally I get back an alpha vector that has a surprising number of non-zero values. Several times the normal. If I actually use that anomalous alpha to calculate the average number of SVs, it will seriously skew the statistics. I checked to make sure that this isn't being caused by all my data points being on one side of the target function line. It isn't. Then the alternative is that it hasn't converged. Or that I have a bug ...
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