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Subject: Re: Modifying a crafty to play at a lower strength

Author: José de Jesús García Ruvalcaba

Date: 03:16:37 10/08/01

Go up one level in this thread


On October 07, 2001 at 21:39:52, Robert Hyatt wrote:

>On October 07, 2001 at 16:37:27, derrick gatewood wrote:
>
>>I am trying to get modify crafty to play at a level that is comparable to my own
>>strength.  I am rated 2055 and I want something that is about 1950-2050.  I have
>>tried creating a resource file with dumbed down options like Search Depth 5 and
>>other things, and I have even tried taking the search depth further down.  Can
>>anybody help me identify and change the resource options I would need to get
>>this thing to play within that range?  What exactly is the selectivity option?
>>Or even better,  if there is some kind of tutorial website that somebody knows I
>>would appreciate it very much!  Thanks,  Derrick
>
>
>Here are the options:
>
>1.  Check the "extension" command in crafty.doc.  You can use this to tone
>down the search extensions and reduce its tactical acuity.  You can set them
>to zero, which will definitely weaken the tactical part of the search.
>
>2.  You can tone down (or even disable) the null-move search.  You can
>try sel=2/3 (the default) then sel=2/2, sel=1/1, and finally sel=0/0 which
>will turn null-move off.  This will further reduce the search depth and overall
>strength.
>
>3.  Check the "evaluation" command and start cutting the "weights" down.  They
>default to 100, so reducing these reduces the influence of "knowledge" in the
>search.  IE reducing the pawn evaluation weight to 25 will reduce the effective-
>ness of pawn structure analysis to 1/4 of its original "smarts".
>

And if you want a really weak crafty, set these evaluation weights to ridiculous
values. Something like either 5000 or -5000 for ksafety, for example.
José.

>It should be possible to play with these to create a program that is tactically
>and positionally as strong or as weak as you would want.  It would probably feel
>wrong to have a positionally smart but tactically stupid program (ie extensions
>zero, positional stuff at default levels) or vice-versa...  But there is a _lot_
>of room for experimentation.  If you find some settings you like, email them to
>me and I will be happy to add a "personality" that uses those settings so it
>will be easy for others to try them out...



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