Author: Gerd Isenberg
Date: 08:05:02 01/23/03
Go up one level in this thread
On January 23, 2003 at 08:38:41, Ulrich Tuerke wrote: >On January 23, 2003 at 05:36:12, Uri Blass wrote: > >>On January 23, 2003 at 03:57:45, Peter McKenzie wrote: >> >>>Sounds like you are doing history heuristic. A couple of points (which you >>>might know already): >>> >>>1) Make sure you have a separate history table for each colour. >> >>I have only one history table. >>Is it important to have seperate history table for each color? >> >>Usually when from->to is often legal for white it is not often legal for black. >> >>I may also get rid of the history table in the future and I guess that there are >>better alternatives for order of moves. >> >>I read that some programmers (like Tony Worten) found that getting rid of >>history tables made their program stronger so I guess that they have other rules >>to decide about order of moves that are simply better. > >I still do use a history table. However, I am not really convinced about its >benefits. Use and Non-Use of history in Comet gives results, which don't suggest >that history is a real help. >In former times, before using a transposition table, a history table was much >more useful than today. TT makes it basically obsolete, IMHO. >OTOH, using it doesn't cost much either. So , I have it still in. > >I even use some similar tables called "butterfly tables", which store moves >which had turned out to refute a special precdeding move at some time. The table >is indexed by the preceeding move. So - ever when I find that the "preceeding >move" is played I look into the refutation table to see whether there is a >potentail killer for this. However, its effects aren't sensational either. > >BTW, this is not my invention, but had been suggested by 2 Dutch authors (iirc, >Hartman - the author of dappet and some co-author) a lot of years ago. > >Uli Hi Uli, i also tried it, shortly after you told me about it in Leiden. It seems to improves my move ordering a bit. I guess this heuristic is also called "Counter Move Heuristic" in M.N.J. van Kervinck's Master's Thesis about Rookie 2.0. Can you explain again, where the name "butterfly table" comes from? Cheers, Gerd > >> >>I have only one 64*64 array like tscp. >> >>Uri
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.