Computer Chess Club Archives


Search

Terms

Messages

Subject: Re: To Martin Fierz: LZSS compression and EGTB

Author: martin fierz

Date: 12:45:36 05/11/02

Go up one level in this thread


On May 11, 2002 at 15:34:58, Alvaro Jose Povoa Cardoso wrote:

>On May 10, 2002 at 18:48:20, martin fierz wrote:
>
>>On May 10, 2002 at 17:25:49, Alvaro Jose Povoa Cardoso wrote:
>>
>>>Hi Martin,
>>>I would like to know your opinion on LZSS for EGTB.
>>>LZSS is extremely fast on decompression.
>>>I tested a 104Mb pgn file with LZSS and it compressed to 35Mb.
>>>I know pgn files is not the intended purpose but do you think it has good
>>>aplicability for EGTB?
>>>
>>>Best regards,
>>>Alvaro Cardoso
>>
>>hi alvaro,
>>
>>i don't even know what LZSS is :-)
>>i'm currently very busy working on my program for the las vegas tournament, so
>>i'm not trying for better database compression at the moment. i have compressed
>>my database from about 37GB to 4.3GB; but it is a lossy compression scheme,
>>removing all positions where a capture can occurr from the database. this makes
>>a lot of sense because these are typically positions with "random" values. the
>>chinook db is compressed to 5.6GB, both mine and the chinook db use run-length
>>encoding.
>
>How do you remove those positions?
>By just storing a zero for example?
>
>Best regards,
>Alvaro Cardoso

by storing a value which will fit in with the adjacent values - so if you have
something like 12101 as values, but the 2 and 0 are in capture positions, you
will save two 1s there. if it had been 21202 instead, you would save 2s instead.
just maximize the run lengths.

aloha
  martin



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.