Computer Chess Club Archives




Subject: Re: Bitbases - yace, scorpio, gambitfruit

Author: Daniel Shawul

Date: 21:21:19 12/06/05

Go up one level in this thread

On December 06, 2005 at 13:16:24, Zappa wrote:

>On December 06, 2005 at 05:07:25, Daniel Shawul wrote:
>>On December 06, 2005 at 04:58:01, Ryan B. wrote:
>>>On December 06, 2005 at 04:41:25, Bernhard Bauer wrote:
>>>>the use of bitbases looks promising. Gambitfruit makes use of Scorpio bitbases.
>>>>Dieter Buersner uses bitbases in yace too.
>>>>Dieter has more files and they are smaller than the scorpio bitbases.
>>>>Would it be possible for the author of gambitfruit to use the bitbases from
>>>>yace? Is there kind of a standard in bitbases?
>>>>Kind regards
>>>I think Danial plans on doing 5 piece bitbases and when they are ready I plan on
>>>supporting them in Gambit Fruit.  I hope people notice what Danial has done with
>>>making his bitbases easy to use and other engines start picking them up.  The
>>>way I see it maybe some idea I use in Gambit Fruit will be seen by another
>>>programmer and help them in some way but likely if a program is not already
>>>using bitbases it can benefit from the use of Danial's easy to use bitbases.
>>  Thanks for the support. I would have used some body else's bitbases myself
>>if i find a free one. Johan Melin (Knight Dreamer) has a similar DLL which can
>>be used by others. But it is not completely free though.
>>For Bernhard:
>> AFAIK yace bitbases are not public. And scorpio bitbases are not larger than
>>yace's. Scorpio takes 18mb, yace takes 21mb, but that is insignificant.
>>For example the compressed bitbases that i have now for 4 pieces are 6mb large.
>>But that hurts speed of the engine. Knight Dreamers bitbases are 1mb in size
>>Engines that i know have bitbases:
>>    KnightDreamer,Yace,Kiwi,Delfi,SlowChess,glaurung,GLC
>How does KD manage to get so much smaller?

KD uses binary dicision trees to store the data. Also for some of the
bitbases it only stores the execptions. Delfi's are even smaller.
There is also a recent paper on compression using ordinary binary decision
diagrams OBDDs, according to the author 4 piece bitbases  take only 1mb.
And the decompression speed is very small (as fast as normal evaluation of a

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