Author: Sune Fischer
Date: 09:21:07 10/04/01
Go up one level in this thread
On October 04, 2001 at 10:19:33, Uri Blass wrote: >>Move ordering has that bit of randomness about it, sometimes you pridict wrong >>and you get the right move second (or even last). >>Most of the time you would get the right move first though (or else just reverse >>move ordering, so that is a safe assumtion). >>Example: >> >>1. move has 60% chance of being the best. >>2. move has 30% chance of being the best. >>3. and rest 10% >> >>Search move 1 => succes has 60% chance. >>Search half move 1 and half move 2 in the same time => 0.5*(60+30)=45% chance. >> >>It will not pay off on average, only once and a while. > >It is not so simple. >programs do not have exact scores for a lot of moves and they search for good >enough moves and not for the best moves. Are we talking about the alpha-beta algorithm here? The better the move ordering you have, the more cut-offs you get and the faster you go, so you want the best moves to be searched first. You can reverse the whole move ordering, it will end up finding the same move (or some with equal score) but it will be alot slower, worst case would be minimax speed. I don't know what the parallel version of A-B() does either, but I figured it was something along those lines. >if 2 processors search for a good enough move then it is possible that they can >find in small part of the cases better good enough move than one processor and >later in the next iterations the computer can remember that better good enough >move to get a better branching factor. > >Uri Yes, "in small part of the cases" agreed, but not on average. -S.
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.