Computer Chess Club Archives


Search

Terms

Messages

Subject: Tablebase Questions

Author: bob o

Date: 10:40:54 03/19/02


1. I think I read something (I could be wrong) where they said that someone made
a program so that some 6-man tablebases could be made in chunks, so that a bunch
of different programs could split up the task of making these gigantic files,
kinda like those guys that are looking for aliens. Does anyone know anything
about that, or was my source incorrect?

2. For Prof. Hyatt: On the ftp site, there are some tbs's for tablebases that
are not available on the site; I think that they are all 5+1 files, I could be
wrong... is it possible to obtain the TB files somehow?

3. When playing around with tbcomp.exe I noticed that if you decompress the
downloaded files and then compress them again with large values for the size of
the encode block size (the -e parameter) you can change (and reduce) the size of
the files; for the 6-man files I tried so far I got very significant size
savings, but I was not able to run them under crafty (I think it said something
like illegal block size or something, it's been a while... I can try again to
reproduce this if requested). Is it possible to compress them in this manner to
get savings in file size? And if it is possible, what are the chess-playing
ramifications of this?

4. Is it possible for a program to need just one of the tablebase files instead
of the pair? For instance, let's say that you had an endgame of: white- ke1 pawn
e2, black- ke8. And suppose you only had kpk.nbw.emd. Is it possible for the
program with white to say, "Ok I know that I have a mate in N moves." Then it
makes a move. Then black says "I can't find the correct TB file. But I found
kpk.nbw.emd. Now let me search every possible black move for me and white's best
reply, and leave him in the worst possible position." It seems that if this is
possible, then you could cut the storage space in half by doing a quick 2-ply
search.

5. I'm not quite clear on what info is in which TB file. For instance, let's say
we have a series of kqkr endings. In which files are the following (kqkr.nbb or
kqkr.nbw)
  1. white's queen vs. black's rook, white to move
  2. white's queen vs. black's rook, black to move
  3. white's rook vs. black's queen, white to move
  4. white's rook vs. black's queen, black to move

Sorry if these questions were answered here before, I am a rather recent
newcomer here, and I do not have a great understanding of TB files, but am
fascinated by them. Thanks in advance.

Bob



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.