Author: Robert Hyatt
Date: 08:50:26 02/08/04
Go up one level in this thread
On February 08, 2004 at 06:40:44, martin fierz wrote:
>On February 07, 2004 at 23:37:31, Robert Hyatt wrote:
>
>>On February 07, 2004 at 18:26:00, Uri Blass wrote:
>>
>>>I started to work on having some evaluation about endgame and
>>>I wrote something to detect draws in KP vs K.
>>>
>>>It does not detect every possible draw but at least hopefully when it detect
>>>draw it is correct if I have no bugs.
>>>
>>>Tablebases is not a solution because they are too slow and I believe that
>>>generally functions are better because even in case of having tablebases if I do
>>>not probe them in the qsearch I may get KP vs K that I need to evaluate without
>>>tablebases and I want to return correct score without looking in tablebases.
>>>
>>>I read that yace is using bitbases even for 4 piece endgames when the bitbases
>>>give only win draw loss information and I guess that the bitbases were
>>>calculated from nalimov tablebases.
>>>
>>>I wonder what other people do in KP vs K endgame in case of not looking in
>>>tablebases(because the program does not support tablebases or because it is a
>>>qsearch node).
>>
>>I have special code. that handles two rules:
>>
>>1. If the king is one square in front of the pawn, and has the opposition,
>>then the pawn queens.
>>
>>2. If the king is two squares in front of the pawn, then the pawn queens no
>>matter what.
>>
>>A couple of special exception cases to make sure that the opponent can't capture
>>the pawn instantly, and you are done... Just try Crafty with KP vs K and no
>>tables, to see what I mean...
>
>umm, i hope you also have some code in there for rook pawns like this - else
>your rules are wrong :-)
>
>e.g. this is a draw but your rule #1 says it's a win.
>
>[D]k7/8/K7/P7/8/8/8/8 b - - 0 1
>
>cheers
> martinBlack(1): end-game phase
clearing hash tables
note: scores are for the white side
material evaluation................. 1.00
development......................... 0.00
pawn evaluation..................... 0.52
passed pawn evaluation.............. -0.30
passed pawn race evaluation......... 0.00
king safety evaluation.............. -0.43
interactive piece evaluation........ -0.79
total evaluation.................... 0.00
I think I got this one right. :) This is part of the bishop + wrong rook pawn
idea, without the bishop. :)
Move them over a couple of files and I get this:
end-game phase
note: scores are for the white side
material evaluation................. 1.00
development......................... 0.00
pawn evaluation..................... 0.58
passed pawn evaluation.............. -0.30
passed pawn race evaluation......... 5.25
king safety evaluation.............. 0.00
interactive piece evaluation........ 0.50
total evaluation.................... 7.03
>
>>
>>>
>>>Do they have a special function to detect the result or do they assume that
>>>cases when they get KPK in the qsearch are rare enough when they use the 5 piece
>>>tablebases because in most cases they probe the tablebases earlier.
>>>
>>>Uri
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