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Subject: Re: The Pawn Game revisited...

Author: Ricardo Gibert

Date: 03:26:40 09/21/03

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On September 21, 2003 at 06:04:34, Uri Blass wrote:

>On September 21, 2003 at 04:59:46, Sune Fischer wrote:
>
>>On September 21, 2003 at 01:00:37, Paul Byrne wrote:
>>
>>I tried a different, even faster position, looks like it's a big zugzwang!
>>
>>[D]8/8/pppppppp/8/8/PPPPPPPP/8/8 w - -
>>1	0	1	1		1.a4
>>2	0	1	17		1.a4 a5
>>3	0	1	58		1.a4 b5 2.axb5
>>4	0	1	235		1.a4 b5 2.c4 bxa4
>>5	0	1	574		1.a4 b5 2.c4 h5 3.axb5
>>6	0	1	1609		1.a4 b5 2.c4 h5 3.h4 bxa4
>>7	0	2	3481		1.a4 b5 2.c4 h5 3.h4 e5 4.axb5
>>8	0	2	8625		1.a4 b5 2.c4 h5 3.h4 e5 4.axb5 cxb5
>>9	0	4	18592		1.a4 b5 2.c4 h5 3.h4 e5 4.b4 d5 5.axb5
>>10	0	5	43157		1.a4 b5 2.c4 h5 3.h4 c5 4.f4 a5 5.e4 bxa4
>>11	0	10	98442		1.a4 b5 2.c4 h5 3.h4 c5 4.b4 d5 5.e4 dxe4 6.dxe4
>>12	0	33	391079		1.a4 b5 2.c4 h5 3.f4 c5 4.h4 a5 5.d4 f5 6.b4 bxa4
>>13	0	73	851266		1.a4 b5 2.c4 h5 3.f4 c5 4.e4 b4 5.d4 e5 6.g4 a5 7.dxe5
>>14	-100	251	2929213		1.a4 a5 2.e4 e5 3.d4 d5 4.b4 c5 5.f4 f5 6.c4 h5 7.g4
>>15	100	1499	17292060	1.a4 h5 2.h4 b5 3.e4 d5 4.b4 g5 5.g4 f5 6.f4
>>16	-100	1976	22723174	1.a4 a5 2.h4 h5 3.c4 f5 4.b4 b5 5.d4 g5 6.f4 d5 7.g4 c5
>>8.e4
>>17	0	2655	30378376	1.a4 h5 2.h4 a5 3.f4 e5 4.c4 f5 5.d4 b5 6.g4 g5 7.b4
>>18	-299982	5394	62233614	1.a4 h5 2.h4 a5 3.c4 c5 4.f4 e5 5.e4 f5 6.d4
>>19	-299982	18708	244756665	1.a4 h5 2.h4 a5 3.c4 e5 4.d4 d5 5.f4 g5 6.e4 f5 7.g4
>>20	-299982	32140	429458855	1.a4 h5 2.h4 a5 3.c4 e5 4.e4 d5 5.f4 c5 6.g4 b5 7.d4
>>g5 8.b4 f5 9.axb5
>>21	-299982	45633	614250543	1.a4 h5 2.h4 a5 3.c4 e5 4.e4 d5 5.f4 c5 6.d4 f5 7.g4
>>22	-299982	59388	802228766	1.a4 h5 2.h4 a5 3.c4 e5 4.e4 d5 5.f4 c5 6.d4 f5 7.g4
>>23	-299982	72952	987563406	1.a4 h5 2.h4 a5 3.c4 e5 4.e4 d5 5.f4 c5 6.d4 f5 7.g4
>>24	-299982	86610	1173582223	1.a4 h5 2.h4 a5 3.c4 e5 4.e4 d5 5.f4 c5 6.d4 f5 7.g4
>>
>>I'm not fond of those eval swings in the middle, but my qsearch had to suffer
>>some simplification, and this being a pure bean counter eval might produce such
>>instability.
>>
>>Perhaps you can confirm it?
>
>I can confirm that it is wrong without programs
>The pv says
>1.a4 h5 2.h4 a5 3.c4 e5 4.e4 d5
>
>White is clearly winning by exd5 so without expressing opinion if white is
>losing this line is not the reason that white is losing.
>
>I think that you should not use hash tables unless you hash all the board.
>They destroy everything and I cannot trust your result because there may be hash
>collision(when you try to solve a game I want result without doubt and the
>situation is different than playing so if I cannot be sure that there is no hash
>collision your solution is wrong.
>
>Evaluation of unstoppable passed pawns may help you to prune stupid moves like
>d5.
>
>Uri


I think he may have broken his qsearch. I wouldn't expect TT's would cause
significant problems here. It's true their use would not lead to an iron clad
result, but nobody can guarantee their program is bug free anyways. Bugs can be
incredibly subtle.



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