Author: Steve Maughan
Date: 03:09:53 10/09/00
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
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