Computer Chess Club Archives


Search

Terms

Messages

Subject: Re: detecting result by evaluation in Kp vs K positions

Author: martin fierz

Date: 03:40:44 02/08/04

Go up one level in this thread


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
  martin

>
>>
>>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



This page took 0 seconds to execute

Last modified: Thu, 15 Apr 21 08:11:13 -0700

Current Computer Chess Club Forums at Talkchess. This site by Sean Mintz.