Author: Dann Corbit
Date: 20:57:24 10/27/05
Go up one level in this thread
On October 27, 2005 at 23:45:08, Yakov Konoval wrote:
>On October 27, 2005 at 22:17:18, Dann Corbit wrote:
>
>>
>>What I would want from a set of EGTB files is the fastest possible access.
>>So if decomression of the block was slower than reading the decompressed block,
>>then the compression is literally "a waste of time."
>>
>
>The krbnkrb EGTB has size about 160 GB (with using zlib.dll). With using
>LZMA-algorithm this size can be reduced approximately up to 100 GB.
>From the other side the fastest possible access is very important for a chess
>playing-program, but not so important for data-mining programs.
>
>>>If you need provably the best compression, then look no further:
>>>http://www.ii.uni.wroc.pl/~inikep/research/pasqda41b.zip
>>>
>>>According to this document:
>>>http://www.maximumcompression.com/data/doc.php
>>>pasqda41b achieved 1.3552 bits per byte against a large body of inputs.
>>>
>>>Comes with source code. But expect it to be a slow, slow memory hog.
>>
>>I looked up that program (pasqda41b), and it is designed for text files. So it
>>probably won't work for EGTB files.
>
>Usually EGTBs can be compressed much better than 8/1.3552 times.
>I know PAQAR4 archiver - it really gives optimal compression, but the speed
>of compression is 4 KB(!!!) / sec.
>(Probably pasqda41b is written by the authors of paqar4 - I'll check it).
LZMA SDK 4.27 seems an interesting idea to try.
It is related to the 7-Zip project.
This:
144,384 lzma.exe
compressed into this:
61,474 lzma.eze
42.6% of the former size (too fast to time).
And this:
6,810,624 AloneLZMA.ncb
compressed into this:
1,720,055 AloneLZMA.nzb
25.3% of the former size in 12 seconds for 567,552 bytes/sec
This page took 0.01 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.