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Subject: Re: Thanks for extracting this!

Author: Alessandro Damiani

Date: 06:48:22 01/01/06

Go up one level in this thread

On January 01, 2006 at 08:53:35, Uri Blass wrote:

>On January 01, 2006 at 07:46:50, Alessandro Damiani wrote:
>>On January 01, 2006 at 06:12:31, Uri Blass wrote:
>>>On January 01, 2006 at 05:24:30, Alessandro Damiani wrote:
>>>>On January 01, 2006 at 02:36:28, Uri Blass wrote:
>>>>>On December 31, 2005 at 20:50:30, Vincent Diepeveen wrote:
>>>>>>On December 31, 2005 at 20:20:47, Greg Simpson wrote:
>>>>>>>Vasik had very logical and persuave ideas.  I particularly liked the point that
>>>>>>>trading one third speed searching for twenty times the evauation per position
>>>>>>>almost has to be good if done right.
>>>>>>If that describes what he's doing then it seems however Vasik has taken the
>>>>>>other way around, the junior way. The utmost minimum of knowledge in leafs.
>>>>>I do not understand this comparison.
>>>>>Rybka is a slow searcher and Junior is a fast searcher.
>>>>>What is the reason that you think that rybka has minimum of knowledge in leafs?
>>>>How do you know Rybka is a slow searcher? Just by looking at its obfuscated
>>>>nps?? For instance, in
>>>>[D]8/8/pppppppK/NBBR1NRp/nbbrqnrP/PPPPPPPk/8/Q7 w - - 0 1
>>>>do you really think it takes quite long to find the mate in 1 because of a huge
>>>>static analysis? ;)
>>>In this case it does not show nodes per second but in the following position
>>>it shows nodes per second
>>>[D]8/8/pppppppK/NBBRQNRp/nbbrqnrP/PPPPPPPk/8/8 w - - 0 1
>>>Analysis by Rybka 1.0 Beta 32-bit:
>>>  +-  (2.46)   Depth: 3   00:02:22
>>>  +-  (2.46)   Depth: 4   00:03:01
>>>1.dxe4 dxe5
>>>  +-  (2.46)   Depth: 5   00:05:22
>>>1.Qxd4 Qxd5
>>>  +-  (2.77)   Depth: 5   00:06:16
>>>1.Qxd4 dxc5 2.Qxe4
>>>  +-  (3.06)   Depth: 6   00:08:19  4kN
>>>1.Qxd4 dxc5 2.Qxe4 Bxd5
>>>  +-  (3.06)   Depth: 7   00:12:59  18kN
>>>(,  01.01.2006)
>>>For some reason it searches only 4000 nodes in 499 seconds.
>>>This really seem strange that static analysis takes so much time
>>>I could believe 100,000 nodes per seconds on My A3000 and even 10,000 nodes per
>>>seconds but less than 10 nodes per second is even too much for me to believe.
>>>It seems that Vasik searches many nodes in what he counts as nodes.
>>>Maybe he is using different function and not using his normal makemove in the
>>>qsearch but it is clear that he searches a lot of legal moves inside of what he
>>>considers as evaluation so I cannot consider it as evaluation.
>>>I think that static analysis can consider trapped pieces so you can consider
>>>some moves without making them to check for trapped pieces but what I see in
>>>rybka is clearly too much for what I consider as static analysis.
>>>I think that recursive search of moves with more than one move per side cannot
>>>be considered as part of the evaluation.
>>Exactly. Static analysis is a 0-ply search, search being an operation which uses
>>making/unmaking of moves.
>>With my previous message I wanted to say this: you cannot imply from low nps
>>that an engine is a slow searcher. For instance, by just not counting quiescence
>>nodes an engine will have a low nps.
>I agree but I do not see a reason not to count qsearch nodes and the author did
>not admit that he does not count qsearch nodes and it seems to me based on his
>posts that he counts every node in his search so I was surprised to find out
>that he does not do it.
>I did not want to believe GCP that rybka does not count qsearch nodes because I
>assumed that Vasik knows more about rybka and I assume that he does not give
>misinformation but it seems that I was wrong and GCP was right.
>Not finding the mate fast is no proof for not counting nodes in the qsearch but
>the small number of nodes in the next diagram is certainly a proof that the
>number of nodes can be very small(less than 10 nodes per second) and searching
>less than 10 nodes per second cannot be explained by something that is not
>recursive search and not something equivalent to recursive search.

I agree. Everyone cooks with water......mmh, maybe I should use my steamer to
improve my engine..... :)


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