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Subject: Re: EGTB: Better algorithm

Author: Uri Blass

Date: 07:33:26 04/08/01

Go up one level in this thread


On April 08, 2001 at 10:26:33, Uri Blass wrote:

>On April 08, 2001 at 09:57:35, Tony Werten wrote:
>
>>On April 08, 2001 at 08:41:19, Uri Blass wrote:
>>
>>>On April 08, 2001 at 06:47:56, Aaron Tay wrote:
>>>
>>>>On April 08, 2001 at 06:14:44, José Carlos wrote:
>>>>
>>>>>On April 07, 2001 at 11:18:34, Urban Koistinen wrote:
>>>>>
>>>>>>I have written down a algorithm for computing endgame tablebases that should be
>>>>>>about 10 times quicker than the Nalimov algorithm and requires much less ram.
>>>>>>It is similar to the Arlazarov&Futer algorithm of 1979 but is more general as it
>>>>>>does not require a pawn.
>>>>>>It might be too technical for most here,
>>>>>
>>>>>  Thank you. Too technical algorithms are not for a crowded-of-programmers forum like this. We wouldn't understand anything.
>>>>>
>>>>>  José C.
>>>>
>>>>Hey , be nice. He's new here.
>>>>
>>>>He is just feeling a little fustrated after posting at r.g.c.c and getting only
>>>>one response. Knowing the high level of general technicial expertise here, I
>>>>suggested to him  that he should post here.
>>>>
>>>>So what do the experts think? Is the algorithim as good as he claims? Layman
>>>>like me want to know!
>>>
>>>1)I tried to explain the paper in more words in order to understand it and the
>>>first part that I did not understand was the sentence:
>>>"t4 depends on t3 and d"
>>>It seems to me that t4 is dependent also on t1.
>>>
>>>Here is an example of position in t4
>>
>>Why is this an example of t4 ? Might be t100, white has just captured a queen.
>>Or t99, black has taken the other white queen.
>>
>>Counting the number of moves for the 50 move rule has nothing to do with
>>distance to mate. ( Or I really don't get it )
>
>1)I understood that it is the distance to conversion or mate(in the case of my
>diagram it is the distance to mate).
>
>Every position must be in exactly one set that is not dependent in the history
>of the game.
>
>If you include the history of the game then generating 6 piece tablebases seems
>to be impossible task.
>
>I admit the explanation is not clear but I tried to understand some logical
>explanation and I guess that the author meant:
>g50=0 when there are no half pawn left to the conversion and g50=100 when there
>are 100 quiet moves until the conversion.

Correction:
it should be 99 quiet moves because g50=1 means tat the first move is conversion
or checkmate and g50=0 means that conversion is not needed
>
>
>2)When I think about it again I understand that my explanation is not right.
>
>t1 can include also positions when black is to move and here is an example:
>[D]8/8/8/kQ6/8/8/7R/7K b - - 0 1
>
>It means that t2 can include also positions when white is to move.
>
>Uri

It does not change the fact that in my example of KQK
finding that a position is in t4 is dependent also on the table t1 and not only
on the tables t3 and d.

Uri



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