Author: José Carlos
Date: 00:32:14 04/21/04
Go up one level in this thread
On April 21, 2004 at 02:52:12, Daniel Shawul wrote: >On April 19, 2004 at 20:38:47, Mike Siler wrote: > >>My program tries a null move search if >> >>1. it's not the endgame >>2. it's not a PV node >>3. it didn't just make a null move >>4. it's not in check and wasn't in check on the previous ply >>5. the remaining depth isn't so small that the reduced depth would take it into >>the qsearch >> >>In general, only around 65% of the null move searches my program performs result >>in a cut-off. Is this normal or do other programs tend to do better (and how)? >>According to Ed Schröder's page, Rebel gets around 93-95%. I've tried the > >I am sure it does get that %. I just did a similar implementation like rebel's > evaluate internal nodes > if(score - our maximum hanging piece > beta) > don't do null move > This gives me usually >93% effectiveness! Thanks Ed. I don't know if Ed does only that, but in my experience it doesn't work. You must also take into account your own threats or you'll do unnecesary full searches. For example, eval is 0 and you have a hanging pawn, while beta is also 0. The opponent has its queen and rook attaked by your pieces. A null move will save a lot of nodes there. The raise in % effectiveness is not enough to compensate for that, in my experience. José C. >>recommendations listed there but they didn't help much. >> >>Michael
This page took 0 seconds to execute
Last modified: Thu, 15 Apr 21 08:11:13 -0700
Current Computer Chess Club Forums at Talkchess. This site by Sean Mintz.