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Subject: Re: Initial Position Search Nodes

Author: Bert van den Akker

Date: 12:04:05 10/09/00

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On October 09, 2000 at 06:09:53, Steve Maughan wrote:

>Having managed to add all the normal stuff to my chess program (hash, SEE
>sorting, null move, killers, internal iterative deepening etc) I am a little
>disappointed with the depths it is reaching.  At first I thought it must be poor
>move ordering but I've checked that and it seems OK (I do Hash Move, Good
>Captures, Killer1, Killer2, History, Bad Captures).  I decided to see how long
>it took to complete it's nineth ply search from the initial position.  Here are
>the results along with those of other programs (450 MHz P2):
>
>MyProgram 31 secs 6,486,200 nodes
>Ikarus 15 secs 888,000 nodes
>HIARCS 18 secs 677,000 nodes
>Faile 50 secs 3,500,000 nodes
>Crafty 17.11 8 secs 800,000 nodes
>Goliath Light 0 secs 31,000!!!!
>Nimzo 7.32 13 secs 3,260,000
>
>A couple of points.  Firstly, how on earth can Goliath search 9 ply so quickly
>and using so few nodes?  I can't beleive that Goliath is the most selective.
>
>Secondly, it would seem that Ikarus' nodes / sec are much lower than indicated
>when calculated using nodes visited divided by time!
>
>Finally, for my program what am I doing wrong?  Am I missing something?  What
>other forms of selectivity are coming into play here?  I'm just doing a vanilla
>Alpha / Beta but it's taking me ages (6 million nodes) to complete 9 ply.
>Perhaps Bob could shed some light on Crafty's impressive 8 secs and only 800 kn.
> Could it be my poor evaluation funtion which is only a primitive piece-square
>table?
>
>All help appreciated!
>
>Regards,
>
>Steve Maughan


Maybe you do more in the quiescence search. If you do a lot of check extensions
in your quiescence search than this will increase the number of nodes a lot.


BvdA




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