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 >place." > >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 once.
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