Author: Stuart Cracraft
Date: 11:04:17 01/03/06
Go up one level in this thread
On January 03, 2006 at 12:53:33, Uri Blass wrote: >On January 03, 2006 at 12:18:58, Tord Romstad wrote: > >>On January 03, 2006 at 11:49:05, Robert Allgeuer wrote: >> >>>On January 03, 2006 at 10:49:54, Maurizio Monge wrote: >>> >>>>What you said is surely true. >>>>But what i find strange is that, IIRC, the only quite new technic in computer >>>>chess that can be found in fruit is history pruning, everything else is just a >>> >>>History pruning was already in use in SmarThink and other engines before as >>>well. If I am not completely mistaken history pruning was invented by Sergej for >>>SmarThink. >> >>It is possible that Sergei introduced the name "history pruning", but the >>technique itself is very old; certainly much older than SmarThink. > >You are right and Movei use it for some years. >First public version of movei to use history based reduction was 07_99 > >I did not talk about it at that time but I used it and I am not going to be >surprised if other also used it earlier. > > I no >>longer remember where or when I heard about it for the first time, but it was >>definitely not in this millennium. >> >>"History pruning" is a really bad name for the technique, by the way. Since >>a long time, I have been advocating to rename it to "late move reductions". >> >>The word "history" is misleading because the technique can be implemented >>without using history counters. > >In this case it is not history based pruning. >I certainly use history counters but it is possible that I can improve it by not >using history counters and using different conditions instead of them. > >Today I use combination of evaluation and history information to decide about >reduction. > > > I currently use a combination of null move >>threat detection and evaluation data to make my late move reduction decisions, >>and don't use history counters at all. This seems to work clearly better, >>at least in my program. > >originally when I implemented it I had no condition about late move reduction >but later I changed it and at least today I never reduce the first move. > >> >>The word "pruning" is misleading because most people don't use the idea >>to prune moves, but only to reduce the search depth. > >I agree that the word reduction is better. >> >>"Late move reductions" is a much more appropriate name, and does a better >>job of explaining what the idea is about: Reducing the depth for the less >>interesting moves late in the move list. >> >>Tord > >The idea is to reduce the depth of moves that you are almost sure that they are >going to fail low. > >Uri And how do you decide this?
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.