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Subject: Re: Rybka nps - 30knps

Author: Uri Blass

Date: 03:59:21 02/07/06

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On February 07, 2006 at 01:37:23, Dann Corbit wrote:

>On February 06, 2006 at 22:25:35, Ryan B. wrote:
>
>>On February 06, 2006 at 21:58:39, Dann Corbit wrote:
>>
>>>On February 06, 2006 at 21:47:09, Ryan B. wrote:
>>>
>>>>On February 06, 2006 at 17:20:00, Alvaro Jose Povoa Cardoso wrote:
>>>>
>>>>>Some time ago I saw someone reporting (don't remember if it was here) Rybka
>>>>>doing 30Knps, while crafy 19.x doing 800Knps and Fritz8 doing over a million nps
>>>>>on his pc while beating both crafty and fritz.
>>>>>
>>>>>Over the years computer programmers said that nps was an importante factor in an
>>>>>engine performance, (and I agree, look at Deep Blue and Hydra).
>>>>>In face of Rybka nps, my question is:
>>>>>What the hell is going on?
>>>>>In this department Rybka seams to prove that nps isn't a factor for performance
>>>>>at all.
>>>>>
>>>>>Please state you opinion on this.
>>>>>
>>>>>best regards,
>>>>>Alvaro Cardoso
>>>>
>>>>Rather it is to hide extra hidden search or for marketing propaganda I do not
>>>>know but I do know Rybka manipulates its node count.
>>>
>>>By what means do you know this?
>>>
>>>>What is really important
>>>>is the tactical strength of Rybka not the NPS.  It will be interesting to see
>>>>what other engines have similar success after going back to try “old” ideas.
>>>>Also not that Rybka is bad in endgames, I think it is rather good, but it will
>>>>be interesting to see how Vas handles the endgame issues in Rybka.  It does not
>>>>seem that it will be as simple as just adding endgame knowledge.
>>>>
>>>>
>>>>Ryan
>>
>>
>>At low depths the node count can go down from one depth to the next.  That
>>should be proof enough as node count should never go down.
>
>It could conceivably happen due to hash table and forced replies.

Reduction in nodes per second can happen but not reduction in the total number
of nodes and I remember a post of enrique that showed reduction of total number
of nodes in rybka at small depth and you probably need slow hardware to
reproduce it.

If you see Reduction in nodes per second after few seconds of analysis with
rybka then the conclusion is that Rybka probably manipulates its node count.

Uri



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