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Subject: Re: speed question

Author: Daniel Shawul

Date: 04:37:21 08/20/04

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On August 20, 2004 at 03:50:21, Ross Boyd wrote:

>On August 20, 2004 at 01:55:19, Daniel Shawul wrote:
>
>>
>>i used to work my chess on a 1.8GHZ PC.
>>On that PC DanChess(slower program) can score good point
>>against some fast programs with high NPS. But now when i
>>changed to a 2.8GHZ PC things are different. my prog has
>>really a very hard time against those engines. My question is
>>both programs are speeded up by the same amount,so why the difference? how much
>>are the other programs benefited? usually i test at 40 moves in
>>3 minutes.what is the equivalent of this on a 2.8ghz pc.
>
>My guess is too many extensions. Extensions are effective on slower PCs but can
>cause tree explosions which then limit the overall search depth. You could try
>applying certain extensions (eg. recaptures, pawnpushes to 7th, simplification
>into pieceless endgames) only when remaining depth <= 3 ply - or something
  in other words , to be less tactical. other than those extensions i also do
  markoff extensions , which seemed to work for me but others found it bad.

like
>that.
>
>Next guess is to improve move ordering and quiescence pruning. Write a SEE
>routine if you haven't already and use it to prune losing captures in the
>qsearch.  All these things drastically reduce the size of the tree...

  i don't think size of my tree is that large. it falls on the
2-3 range. Problem is i think the large attack table generator in eval which
is taking more than 60% of eval time.i am not going to remove that because i
am using it for lots of purposes right now. my choice is to take advantage of
it for pruning based on eval which might reduce tree size.

  thanks
daniel


>
>Hope this helps,
>
>Ross



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