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Subject: Re: definition of nodes/sec ?

Author: Tony Werten

Date: 13:24:38 02/24/01

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On February 23, 2001 at 16:16:23, Severi Salminen wrote:

>On February 23, 2001 at 13:13:42, James Swafford wrote:
>
>>On February 23, 2001 at 11:19:20, Rafael Andrist wrote:
>>
>>>How is nodes per second defined (or what is usually meant)? Are all nodes
>>>included, or is it without quiescent nodes? Is the hash table disabled to
>>>measure this value?
>>>
>>>Rafael B. Andrist
>>
>>Most folks try to count interior, frontier, and quiescent nodes.
>>You can measure this by entrances to the search / qsearch functions,
>>or by make, etc.
>>
>>I don't think there's a concrete definition, which makes comparison
>>between programs meaningless.
>
>Well I think that the most of chess programs count all visited nodes - there is
>not too much to interpret on that one. So whenever we enter a "new" node we
>increment a counter.

Yes, but do you count make_move or do you count every time you enter search. It
makes a difference if you generate illegal moves, make them and discover you're
in check. You did do a make_move but not a new entrance in search ( or maybe you
do and jump out if you can take the king )

Lots of interpretations. But still it's impossible to compare programs. I do
things in my evaluation that can save me a few ply of search. So I have low nps
but good effective depth.

A good example of this is checking if your passed pawn is out of reach of the
opponents king ( and he has no other pieces ) It takes time but can save you 10
ply of search easily.


>
>The biggest difference is probably whether to count the root node or not... Of
>course there might be programs calculating the first qnodes twice (incrementing
>at the beginnig of search() and then again in qsearch()), but there is no way to
>find that out, except when NPS rate is very high ;)

I knew a guy who was a bit ashamed of his low nps that he actually did
inc(node_counter,7) But then again, he had very original other ideas as well.
One of the best was the amateur-professional heuristic. He noticed that his
program would play nice against professionals but then somewhere thought he
could win a piece only to find out a few ply later that he had just wrecked his
position. So his heuristic was: If you play a better engine and think you can
win a piece, prune this line because it isn't good.

Worked very well, extending his losses with at least 20 moves. He threw it out
when once he played a good engine and could have won a piece.

Tony

>
>Severi



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