LFD Book Forum Clarification Request On Problem 13
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#1
09-12-2012, 09:04 PM
 munchkin Member Join Date: Jul 2012 Posts: 38
Clarification Request On Problem 13

If a data set is not separable using RBF in the Z-space then the QP solver will hit the iteration limit and bomb. If the solver completes and returns an alpha vector that happens to provide zero in-sample error with the test data set then how does that indicate that the training data was not linearly separable? Is every occurrence of zero in-sample error during testing to be interpreted as a failure to separate the training data? I don't understand the operating procedure specified by the problem text.

Thanks for your attention.
#2
09-12-2012, 09:27 PM
 yaser Caltech Join Date: Aug 2009 Location: Pasadena, California, USA Posts: 1,477
Re: Clarification Request On Problem 14

Quote:
 Originally Posted by munchkin If a data set is not separable using RBF in the Z-space then the QP solver will hit the iteration limit and bomb. If the solver completes and returns an alpha vector that happens to provide zero in-sample error with the test data set then how does that indicate that the training data was not linearly separable? Is every occurrence of zero in-sample error during testing to be interpreted as a failure to separate the training data? I don't understand the operating procedure specified by the problem text. Thanks for your attention.
If you get 's that achieve zero in-sample error, then the training data is separable by definition (those separating 's are an existence proof of that fact).
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#3
09-12-2012, 10:44 PM
 munchkin Member Join Date: Jul 2012 Posts: 38
Re: Clarification Request On Problem 14

Thanks for the prompt response.

Ein of zero is perfectly separated. I understand that. Perhaps my confusion arose from thinking about the PLA and how it can fail spectacularly when confronted with non-separable data. I had the impression that missing a few target function points during the in-sample error calculation wasn't a problem of the same magnitude as the solver being unable to converge to any solution at all.

I will talley up the Ein=0 statistics as specified in the problem instructions. Thanks.

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