Author: Albert Silver
Date: 10:59:13 01/06/06
Go up one level in this thread
On January 06, 2006 at 12:55:27, Uri Blass wrote:
>On January 06, 2006 at 12:07:11, Albert Silver wrote:
>
>>>>>>These numbers seem so imbalanced. I wonder if there is not some sort of bug in
>>>>>>the fritz gui or something.
>>>>>>
>>>>>>best
>>>>>>Joseph
>>>>>
>>>>>Your title is misleading so I changed it in my reply.
>>>>>My opinion is that Rybka searches x+2 plies when it claims to search x plies.
>>>>>
>>>>>From my experience it can see at fixed depth of 1 ply things that other programs
>>>>>see at fixed depth of 3 plies
>>>>>
>>>>>Here is an example
>>>>>
>>>>>[D]3k2r1/ppb5/3p4/r2N1p2/8/8/1P6/1K2RB1R b - - 0 1
>>>>>[D]3k2r1/pp1b4/3p4/r2N1p2/8/8/1P6/1K2RB1R b - - 0 1
>>>>>
>>>>>Rybka does not capture the knight at depth 1 in the first case but capture the
>>>>>knight ar depth 1 in the second case.
>>>>>
>>>>>Can Vasik explain why?
>>>>>
>>>>>evaluation?
>>>>>I do not believe it.
>>>>>
>>>>>It must be search and rybka search after Rxd5 Bc4 black move and see that in the
>>>>>first case no move save black from a loss of full rook when in the second case
>>>>>it searches Rxd5 Bc4 Bc6
>>>>>
>>>>>Uri
>>>>Hi all,
>>>>
>>>>It's clearly seen that Rybka uses some form of selective search different from
>>>>others' in the quescence search which is not a full width search, therefore is
>>>>not counted in nps. This explains the low nps, Rybka does extra work in the QS
>>>>which pays off.
>>>>Obvious, that a usual 1 ply search cannot be such better even with a superb
>>>>evaluation but a Rybka-type can be.
>>>>
>>>>Regards,
>>>>László
>>>
>>>No
>>>
>>>It is not clear
>>>
>>>I can achieve the same effect by not counting nodes in the qsearch and writing
>>>depth x when the real depth is x+2
>>>
>>>It is possible that rybka does nothing special except playing better when vasik
>>>tries to hide what it does by misleading information.
>>>
>>>Uri
>>
>>With all due respect, shouldn't you try to get more information before making
>>such suggestions? For example, another program famous for its low full-width ply
>>counts is Hiarcs, and in an exchange between Vasik and Enrico, Vasik said he
>>thought that both he and Uniacke did similar things though withut seeing the
>>source code, it was impossible to confirm. If Hiarcs were equally successful,
>>would you also accuse Uniacke of 'misleading information'?
>>
>> Albert
>
>I showed in the past a position when rybka can search less than 10 nodes per
>second on my fast hardware so it seems clear that his definition of nodes is not
>correct and that rybka does a lot of search inside what is defined by it as a
>node.
Sure, and Vasik has openly admitted that the node count was fairly meaningless
in this aspect. He even said he might artificially double the node count to
reduce the comments or questions on this. So talking about problems of the node
count seems fairly pointless.
Getting back to Hiarcs though, the point is that Hiarcs has long had very low
ply-depth announced, and yet was still able to compete with other top engines.
No one accused Uniacke of deliberately trying to deceive his fellow programmers
or customers. I even remember the discussions on Hiarcs's superior ability "per
ply". You could then point out Junior's unorthodox ply count as well.
What's the point though? You know as well as any that trying to compare plies
between engines or node counts is pointless so why the sinister suggestions for
Rybka?
Albert
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