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Subject: Re: Endgame position / running passed pawns

Author: blass uri

Date: 15:35:10 06/05/00

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On June 05, 2000 at 12:12:24, Ernst A. Heinz wrote:

>On June 05, 2000 at 12:02:22, Ernst A. Heinz wrote:
>
>>Hi Steffen,
>>
>>>[D]5k2/7K/6P1/1p3p2/1P5P/1Pb5/8/8 w
>>>
>>>White is obviously winning. The static evaluation of this position of my program
>>>is totally wrong because Hossa thinks that the pawn f5 is running. Even after
>>>some improvements Hossa needs 8 plies to see a positive score!
>>
>>"DarkThought WCCC'99" sees White winning from iteration #4 onwards.
>>
>>I suspect that you need carefully tuned extensions for pushes of
>>passed Pawns to find this early and quickly.
>
>By "carefully tuned extensions" I mean such that do not blow up
>the search tree like hell.
>
>For the position above, "DarkThought WCCC'99" still completes
>iteration #13 in less than a second.
>
>=Ernst=

It is possible that dark thought can find it faster also because of a better
evaluation function.

[D]5k2/7K/6P1/1p6/1P3p2/1P6/8/8 b - - 0 1

In this position the static evaluation of Crafty is advantage for black because
it does not know that the white pawn cannot be stopped.

It plays f3 with 4.96 pawns advantage for black at depth 1.
It is possible to know by evaluation that the white pawn also cannot be stopped
because the white king controls g7 and g8

Hiarcs has no problem to see at depth 1 that white is winning even before this
position.

I do not know if it see it by search or evaluation because I have no way to see
the extensions of hiarcs at depth 1.

Uri



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