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Subject: Re: NPS

Author: Chris Whittington

Date: 01:15:24 11/14/97

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On November 14, 1997 at 03:30:27, Andreas Mader wrote:

>Chris has claimed many times that his CSTal only searches 4000 NPS and
>performed very well in Paris, whereas the 'fast searchers' (>100
>KiloNPS) had their problems.
>
>This is of course true, but it leads to a question: How do you count the
>NPS? I don't know if this has been asked before, but I would like to
>know, how different programs are counting NPS. Can it be that Chris is
>simply the 'king of understatement' because he uses a different
>algorithm?

I'm pretty sure I count in the standard way; here my method, Bob or
whoever can say if its standard or not .....

CSTal tree searches, like everybody else.

At each node it does the following:


makemove
evaluate
if (extend_this_node)
{
  do a hash lookup - it might find a mtach and cutoff here
  go one more deeper, recursively and return back to here
}
unmakemove
if score>alpha etc

the above process count for ONE node.
if the hash finds a cutoff it still counts for ONE node
if the node gets extended then we add more nodes by the same process


>If you find a position in the hash tables, do you count it?

yes, as one node, as described above

>If a position has a 'clear' material balance so that you do not need to
>do some 'fine tuning' in the evaluation function, do you count it?

CSTal doesn't do a lazy eval, since the eval function can produce very
large scoring swings. Only MATERIALISTS do lazy evals :)

So not applicaple.

>When you do quiescence search, do you count the NPSs?

CSTal doesn't work to this MATERIALISTIC algorithm. Any node, extension
or whatever you want to call it gets counted.

>etc. etc.
>
>Could it be that the 'real' factor between knowledge based programs and
>fast searchers is not that big (4000 : 200.000)?

Don;t think so, but comments welcome ....

Chris

>
>Best wishes
>Andreas



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