Computer Chess Club Archives


Search

Terms

Messages

Subject: Re: q-search question

Author: Andrew Dados

Date: 11:08:23 07/19/00

Go up one level in this thread


On July 19, 2000 at 14:00:16, Landon Rabern wrote:

>On July 19, 2000 at 13:22:47, Andrew Dados wrote:
>
>>On July 19, 2000 at 12:03:10, Landon Rabern wrote:
>>
>>>I have been discarding all captures where attackervalue>DefenderValue in my
>>>q-search which speeds it up significantly, but I know that it is throwing away
>>>some captures that are good.  So I implemented a SEE function.  The SEE returns
>>>the correct value on tests I have run.  When I put this into my program so that
>>>if (attackervalue>DefenderValue)&&(SEE>=0) I keep the move as well, I got worse
>>>results on the WAC test suite.  Before I put the see in I got 270/300 at 60
>>>seconds per move and after I got 257/300 at 60 seconds per move.
>>>
>>>Is it just that there are no capture sequences in this test that need the extra
>>>captures, or is there something wrong with my SEE function?
>>>
>>>Thanks for any help,
>>>
>>>
>>>Landon W. Rabern
>>
>>It would be of help if you post some relevant positions. I may just guess now
>>that if you do check detection in qsearch you may find some mating combinations
>>with 'losing captures', when recapturing piece is overloaded simply, so in next
>>move capture is mate. (Or you may do some non-capturing,checking moves in
>>qsearch which complicates matters still). With SEE you miss those. Question is
>>if average speedup of SEE in non-tactical positions offsets those few missed by
>>using SEE....
>>
>>-Andrew-
>
>I do not do checks in q-search.  The problem is that I should be missing fewer
>tactical positions with SEE, than with just throwing all captures out where
>attackerValue>defenderValue.
>
>Landon

So maybe you are much faster then SEE with throwing away all captures where
attackerValue>defenderValue... Single out those positions and compare PVs and
nodes produced with both versions of your qsearch ply by ply. Then maybe you/we
can learn what's going on. Do you reach extra ply or does your program find
those moves one/few plys sooner?

-Andrew-




This page took 0 seconds to execute

Last modified: Thu, 15 Apr 21 08:11:13 -0700

Current Computer Chess Club Forums at Talkchess. This site by Sean Mintz.