Computer Chess Club Archives




Subject: Re: not using nullmove?

Author: Dann Corbit

Date: 10:57:18 02/18/04

Go up one level in this thread

On February 18, 2004 at 07:00:53, Tim Foden wrote:

>On February 18, 2004 at 04:24:54, Dann Corbit wrote:
>>On February 18, 2004 at 03:36:14, Tim Foden wrote:
>>>On February 17, 2004 at 20:55:13, Dann Corbit wrote:
>>>>Here's a dumb idea:
>>>>Write a program to scan a Nalimov database, but throw away everything except
>>>>won/lost/drawn/broken (needs 2 bits per reflected board position to store the
>>>>outcome state).
>>>>Then write a table.
>>>>For up to the 4 man tables, it should be really tiny and fit into ram without
>>>>any fuss.
>>>>Seems like one single program could write a recognizer for anything [for which a
>>>>Nalimov or Edwards or Thompson EGTB exists].
>>>This is almost exactly the idea that is well documented in Heinz's book!  :)
>>>He gets all the required 3+4 piece tables to fit in just over 15 MB.
>>I read his book, but I don't remember his suggestion of canibalization of
>>existing tb files to create bitbases.  I do remember the notion of extreme
>>compression of bitbases.
>He generated his smaller bitbases from the Edwards ones.  He had to do some work
>to generate correct KPKP ones though.
>The indexing schemes are talked about extensively in chapter 5.  In chapter 6 he
>talks about "Knowlegeable Endgame Tablebases", which use knowledge, including
>"bitbases" to encode tablebase knowledge that can be held in memory.
>Ch 6, p 100, para 3, "Interestingly enough, we derived the necessary a-priori
>knowledge from Edwards' distance-to-mate tablebases [67] and their result
>summaries as publicly available on the Internet.  Hence, Edwards' standard
>tablebases provided the ombiscient feedback which not only enabled but actually
>sparked the development of our knowledgeable endgame databaes in the first
>Ch 6, p 112, para 2, "We created the knowledgeable endgame databases of
>DarkThought with the help of a double-checking tool that automatically converts
>Edwards' tablebase files into our knowledgeable format."

Since I read the whole book, probably my clever idea is just a recollection of
something I already read and forgot.  Reminds me of a "Columbo" episode I saw

This page took 0.15 seconds to execute

Last modified: Thu, 07 Jul 11 08:48:38 -0700

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