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Subject: Re: Does swap of Crafty find bad promotions

Author: Uri Blass

Date: 01:18:26 01/12/04

Go up one level in this thread


On January 11, 2004 at 20:55:32, Mike Byrne wrote:

>On January 11, 2004 at 17:55:11, Uri Blass wrote:
>
>>On January 11, 2004 at 16:52:09, Robert Hyatt wrote:
>>
>>>On January 11, 2004 at 15:47:04, Uri Blass wrote:
>>>
>>>>I do not see a word about promotions in swap.c of Crafty but maybe there is
>>>>something that I do not understand.
>>>>
>>>>Uri
>>>
>>>Swap() will only find capture promotions.  It really doesn't do anything
>>>with them, because the value is a pawn, not a queen, and the normal Swap()
>>>code handles that just fine.  IE if you treat it as simply dxe8, that is
>>>good enough, you are winning a piece.  If your opponent re-captures, he
>>>only gets a pawn, not the queen you promoted to...
>>
>>If the pawn is pinned you may need to capture with something else.
>>
>>[D]rn6/P7/K7/8/8/6k1/1Q6/8 w - - 0 1
>>
>>If I understand correctly
>>SEE of Crafty is going to consider QxN as a bad capture.
>>
>>Uri
>
>
>sd=1
>Black(1): rn6/P7/K7/8/8/6k1/1Q6/8 w - - 0 1
>White(1): go
>end-game phase
>              clearing hash tables
>              time surplus  29.75  time limit 22.87 (3:33)
>              time surplus  29.75  time limit 22.87 (3:33)
>              depth   time  score   variation (1)
>                1     0.00  11.45   1. Qxb8+ Rxb8 2. axb8=Q+
>                1->   0.00  11.45   1. Qxb8+ Rxb8 2. axb8=Q+
>              time=0.00  cpu=100%  mat=2  n=39  fh=100%  nps=10K
>              ext-> chk=1 cap=0 pp=0 1rep=0 mate=0
>              predicted=1  nodes=39  evals=11
>              endgame tablebase-> probes=0  hits=0
>              SMP->  split=1  stop=0  data=1/64  cpu=0.00  elap=0.00
>
>White(1): Qxb8+
>              time used:   0.00
>Black(1):

depth=1 is enough here to see here Qxb8+ because after one ply search you have a
different position.

Uri



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