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Subject: Re: legal move generator that is 20 times faster than Crafty

Author: Carlos del Cacho

Date: 15:58:07 07/02/01

Go up one level in this thread


On July 02, 2001 at 00:44:30, Robert Hyatt wrote:

>On July 01, 2001 at 15:05:44, Carlos del Cacho wrote:
>
>>On July 01, 2001 at 13:21:04, Uri Blass wrote:
>>
>>>On July 01, 2001 at 12:58:40, Bruce Moreland wrote:
>>>
>>>>On July 01, 2001 at 06:44:23, Uri Blass wrote:
>>>>
>>>>>On July 01, 2001 at 05:09:45, stefan wrote:
>>>>>
>>>>>>
>>>>>>see also
>>>>>>
>>>>>>http://members.tripod.com/~RyanMack/hypertech.htm
>>>>>
>>>>>If it is truth than it seems that we are going to see a progress of more than
>>>>>200 elo in comp-comp games only because of better software for the PIII
>>>>>hardware.
>>>>>
>>>>>I have not enough knowledge to understand if he is right
>>>>>
>>>>>Uri
>>>>
>>>>If the move generator in my own program took zero time it would increase in Elo
>>>>points by maybe 20 or 30, and that's probably high.
>>>>
>>>>bruce
>>>
>>>You are right that only move generation is not enough but the point is that I
>>>understand that the data structure helps to do everything faster.
>>>
>>>He suggests in the last 3 lines when you click on the link that the program can
>>>see 10,000,000 nodes per second with the evaluation function
>>
>>I can't see how you can extract useful attack information from a reversed
>>bitboard (without being costly) so the evaluation function is going to be quite
>>stupid or it's going to rely on preprocessing.
>>
>>The method he describes is faster for move generation than rotated bitboards for
>>sure, but I don't think it's going to be faster than mailbox or 0x88 (just my
>>opinion). I may be wrong but we won't see an Hyperbola engine going to 10 Mnps
>>this year, he'll probably have to wait for a long time before release :-)
>>
>>Carlos
>>\\\
>
>
>
>
>
>I didn't see any evidence that it is faster.  The "compact attacks" way it is
>done in crafty is very cache-friendly.  And it produces the attack bitmaps
>on a complete rank or file, in one operation.  The approach given takes 4
>steps for rooks/bishops, and 8 for queens.

I was talking for myslef. It sounds as if it were faster than what I'm doing (I
followed an excellent introduction to bitboards by James Swafford). I'll take a
look at your compact attacks scheme, though I think I didn't got to understand
how it worked when browsing through Crafty's code. Maybe you could enlighten my
narrow mind on the subject.

Anyway there are dubious claims in that document, I don't see how you can make a
move generator 30 times faster than crafty's, so I doubt if he ever got to
implement it, and if he did what was the HW difference he used to measure it.
This person sounds like a day dreamer to me.


>I don't believe it is faster at all.  It avoids updating two bitboards which
>means that the table lookup move generation approach won't work.  That does
>save time.  But how does this approach gain over the direct simplicity of real
>rotated bitmaps when actually generating moves?
>
>I think someone wrote this description without knowing exactly what I am
>doing, using Crafty for my example...
>
>
>
>>>
>>>If you rememeber that nodes is only legal move because he talked about legal
>>>move generator then the result is more impressive.
>>>
>>>We need to wait and see if he is right.
>>>
>>>Uri



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