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Subject: Re: Rybka nps - 30knps

Author: Tord Romstad

Date: 00:21:09 02/07/06

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On February 06, 2006 at 21:47:09, Ryan B. wrote:

>Rather it is to hide extra hidden search or for marketing propaganda

Marketing propaganda?  What does the nodes/second ratio have to do
with marketing?

>I do not know but I do know Rybka manipulates its node count.

"Manipulates" is a too negatively loaded word.  It implies something
dishonest, when it is perfectly possible (and IMHO much more likely)
doesn't do quite the same kind of work at each node as most other
programs.

The exact definition of a "node" differs between different programs,
and even if Rybka uses the most common definition (one node for
each call to search() or qsearch()) the behavior you observe (high
tactical strength compared to the N/s, very irregular N/s depending
on the position) isn't really that strange.  It could be, for instance,
that Rybka is moving the pieces around a lot on the internal board at
each node in order to decide just how static the node is, and use this
to make search decisions.  Such internal, "horizontal" searches at
each node could easily reduce the N/s count a lot, while preserving
tactical strength.  It also makes a lot of sense that the N/s is much
lower in tactically messy positions.

This is just one of many possible explanations, of course.  In any
case, I think "manipulate" is an unfortunate word to use.

Tord



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