Computer Chess Club Archives


Search

Terms

Messages

Subject: test your program use of partial tablebases

Author: Uri Blass

Date: 02:56:42 01/31/05


[D]8/6P1/k6P/7K/p7/8/8/8 w - - 0 1

give your program the kpp vs kp tablebases but do not give it tablebases after
promotion of the pawn.

What does your program play

Latest private movei play h7 because this move reduce the distance to mate.
It still does not know to use tablebases inside the search and I only wrote a
function to teach it to find the best move if the root position is a tablebases
position.

It simply look for the root position and the position one ply later and if it
find a good move based on the scores(reduce the distance to mate(otherwise it
does not probe the tablebases)

Fritz8 with the same tablebases does not see that h7 is mate in 6 inspite of
doing 7 probes and it takes it long time to see mate in 10.

I still did not implement probing tablebases not in the root but the next step
is not hard.

I plan to have a variable probe_tbs and probe_tbs will be 1 except cases when
the root position is tablebases position and I did not find good moves when I
did a loop on the legal move to find a good move.

I find that Crafty does not do it and it needs search to depth 2 to find the
mate score.

Movei needs no normal search and the first step in case that the root position
is a tablebase position is to do a loop on the legal moves that stop only when
it finds a move that reduce the distance to mate or keep the draw(I may change
the last part in order to try to win drawn positions like KRB vs KR when it has
the material advantage).

How to use tablebases in the root is one question and how to use tablebases in
the search is another question.

I wonder how many programmers seperate between these 2 questions in their
search.

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.