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Subject: Re: knowing when you've improved your evaluation function

Author: Dann Corbit

Date: 14:16:39 04/16/04

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On April 16, 2004 at 16:53:40, Dave Gomboc wrote:

>On April 14, 2004 at 19:48:53, Dann Corbit wrote:
>
>>On April 14, 2004 at 19:46:18, Dave Gomboc wrote:
>>
>>>On April 14, 2004 at 18:17:07, Dann Corbit wrote:
>>>
>>>>I have downloaded the document and skimmed it.
>>>>
>>>>I will read it carefully this weekend.
>>>
>>>In that case you might as well re-download it when you sit down to read it.
>>>I've already made some tweaks that aren't yet posted.
>>
>>I am curious about the "wandering" evaluation terms.
>>
>>I suspect two things about these terms:
>>1.  That [usually] the correlational coefficient will be much smaller for these
>>2.  That they occur in pairs {or vectors} (e.g. if wildly different sets can
>>both have nearly optimal results, then likely there are interactions)
>
>I'm not sure what you mean by #1.

The correlational coefficient is the goodness of the fit, for whatever gradient
you are following.  If (for instance) the gradient was tracing out a straight
line and all the points were exactly on the line, then the correlational
coefficient will be 1.0.  That means that there is a powerful relationship and a
direct determination.  On the other hand, if most of the points were well off of
the line, then the correlational coefficient will be small.  A correlational
coefficient of about 0.3 is considered as insignificant such that we cannot tell
if there is any relationship between the variables.

E.g. strongly correlated:

       *
      /
     *
    /
   *
  /
 /
*

E.g. not correlated:


*
           *
   *
       *
 *
          *
   *
>
>Regarding #2, my experience is that there are indeed many interactions.
>
>Some features contribute only a small amount to the evaluation function quality
>-- the weights of such features can have a wider range without penalizing
>effectiveness too highly.  It'd probably be better to find better features,
>though. :-)
>
>Dave



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