Author: scott farrell
Date: 05:27:32 01/15/03
Go up one level in this thread
On January 15, 2003 at 07:42:14, David Rasmussen wrote: >On January 15, 2003 at 07:35:38, Uri Blass wrote: > >> >>I do not see how null move pruning effect stalemate detections. >> >>Cases when my evaluation detects stalemate immediately after null move are very >>rare and I do not see how these cases can do demage to the program. >> > >I'm not saying that any of these things "damage" the program, I just want to be >absolutely clear *why* not, if not. > >In normal situations the logic of null move pruning makes sense: >"If I do nothing, how good can my opponent do?" >But in the presence of repetitions, fifty moves rule and stalemate, it becomes >kind of pathologic, I think. >"If I do nothing, he/I is/am stalemate" or >"If I do nothing, he/I will reach the fifty moves rule" >"If I do nothing, there I/he can force a repetition" >All of this makes no sense, since a null move isn't legal. > >/David I think you have it slightly mis worded. It should sound more like this: If I dont do anything about it, things will probably deteriate to draw. This might be a fail-high, which means the move is too good, and the opponent wont let things get here in the tree, lets just fail high righ now. If it isnt a failhigh, it was a waste of time. So maybe if it is nearing a draw, and beta is less than a draw, the null move might help. If it is nearing a draw, and a drawscore wont fail high, then you'll just be wasting nodes/time. Obviously, you have to be really careful when checking for draw by rep as you go through the nullmove barrier. Scott
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.