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Old 05-27-2013, 08:17 PM
mvellon mvellon is offline
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Join Date: Apr 2013
Posts: 9
Default Re: on the right track?

I'm stuck half-way in this problem. I'm trying to use the C# version of libsvm and, I think it's working, but I can't corroborate the numbers I'm seeing here. Actually, I match on the # of support vectors, but my Ein and Eout numbers are significantly different.

For 0 vs. 7 with Q=2 and C=.01 I get 861 SVs but using Sign(svm_predict) and counting sign mismatches I get:

Ein=.060 and
Eout=.057

Looking at 2 vs 8 with C=.1 and Q=3, I get 721 SVs but errors are much worse:

Ein=.67
Eout=.63

Since I'm getting the right number of support vectors, I think things are somewhat ok, but I'm perplexed regarding the results from svm_predict.

One dumb question: I presume the right way to feed data into libsvm (using its data file reading capabilities) is to manually subset the data as well as to prep it for libsvm format. Is this correct? When processing 2 vs 8, for example, I'll generate a +1 for "2" data, a -1 for "8" data and then discard the rest. Is this the right approach?
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