Author: Ed Schröder
Date: 04:08:27 12/30/02
Go up one level in this thread
On December 30, 2002 at 05:53:16, Martin Giepmans wrote:
>On December 30, 2002 at 05:30:45, Ed Schröder wrote:
>
>>As it seems I have completely mishandled explaining Reduction 2b and 2c, I have
>>corrected things.
>>
>>http://members.home.nl/matador/chess840.htm
>>
>>Click on the blue "update" picture, it will move you directly to the changes
>>made. That will be standard procedure from now on in case of errors.
>>
>>if (remaining_depth<=x && remaining_depth>1) then
>> { if (ALPHA < SCORE + THREAT) -> do not reduce
>> if (ALPHA < SCORE + THREAT + MARGIN) -> reduce depth with one ply. }
>>
>> SCORE : score of EVAL
>> THREAT : Queen=900, Rook=500, Bishop=300, Knight=300, Pawn=100
>> MARGIN : TABLE [remaining_depth];
>>
>> static int TABLE[]= { 00,00,10,15,20,25,25,25,25,25,25,25,25,25,
>> 25,25,25,25,25,25,25 ........... };
>>
>>The idea is, if SCORE+THREAD are not going to make it to ALPHA, but with an
>>extra small MARGIN it will then reduce the depth. I can't remember the speed-up
>>this reduction gave.
>>
>>====
>>
>>Ed
>>
>>PS, the "faulty stuff" plus Uri's correction is maybe worth a try, who knows :)
>The < in the second formula should be > ?
>Otherwise the two formula's together don't make sense.
>(if the first is true, the second is also true)
For free-style pseudo code it is defendable, maybe in more c-code style would
make it more clear?
{ if (ALPHA > SCORE + THREAT &&
ALPHA < SCORE + THREAT + MARGIN) -> reduce depth with one ply. }
ALPHA=100
SCORE=90
THREAT=0
MARGIN=20
-> reduction
ALPHA=100
SCORE=60
THREAT=0
MARGIN=20
-> no reduction
Ed
>Martin
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