Author: John Stanback
Date: 17:55:31 06/29/99
Go up one level in this thread
On June 28, 1999 at 08:56:53, Inmann Werner wrote: I use a window of (beta-1,beta) for null move searches and it gives me a little speedup in Zarkov. Of course, don't forget to change the window to reflect the correct side to move, ie the window becomes (-beta,1-beta) from the opponent's point of view. John >I use Null Move now for one year and works fine. >I make the null move and call alpha-beta with (alpha,beta,distance-3). > >Now I read, and it seems logical to me, that (beta-1,beta) would be enough. I >tried it and everything slowed down (tree bigger!)... Oops. > >I tried to figue out why, and think now, it is because of the hash tables. >During the null move, only beta-1,beta is searched and stuffed in, and so i get >later less "finds" in hash table(the bounds say no for fails). That was, what i >figured out. Surely, this only happens in PV changing, cause there I have a more >open window. >Normally, entrys in hash with null moves should have other hashpositions than if >no null move occured, and therefore the behaviour is strange. > >If I make a null move for white I change the hashadress with a special hashcode, >and if it is a black nullmove I use another code. Is this normal?, or do other >programmers do it another way? > >Werner
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.