Author: Aaron
Date: 08:53:27 03/08/98
Go up one level in this thread
On March 06, 1998 at 22:51:02, Robert Hyatt wrote: >On March 06, 1998 at 20:41:44, Stuart Cracraft wrote: > >>For a long time, my program had been sparring with >>another program. The result over 50 games was about >>40 losses and 10 draws. Never a win. >> >>I suspected a misbalance of positional factors which >>resulted in >1 pawn positional contribution to the >>evaluation score as well as poor development and >>poor analysis of backward pawns. >> >>It seemed likely that by improving the development and >>backward pawn factors and minimizing the positional >>contributions swaying the material score, this might >>help. >> >>So I converted to millipawns (a 5 second change for >>me and a 10 minute compile). Also I added David Levy's >>development terms from "The Joy of Computer Chess" >>and added analysis of backward pawns. >> >>Then I played it against its sparring partner and it >>immediately won its first game. There were no outright >>technical blunders and it kept the game together. >> >>I think another good approach is to analyze your >>worst/largest positional contribution to the overall score >>and find out what kinds of positions are producing these >>big swings in the score that are not materially based and >>start lessening the heuristic scores to bring the positional >>score back within a narrow window. >> >>For example, a king scoring function that results in massive >>changes in the positional score could be a blunder-creator >>not a king-saver! By going to millipawns first it's possible >>to see a formerly blundering program actually play half-decently >>while still working the behind-the-scenes bugs. Later, centipawns >>could be restored, if desired, so that positional sacrifices might >>be made on a more conservative basis. >> >>I am curious regarding the other program's authors on this bulletin >>board, what are the largest positional heuristics you award or >>penalize positions for? And do you use centipawn or millipawn >>and why? And have you experimented with the other and why not? >> >>--Stuart > > >I started with centipawns, switched to millipawns, then back to >centipawns >again. I don't believe that *I* can accurately divide a positional >score >into fractions of 1/1000th... I don't even believe I can divide it into >pieces of 1/100th... > >I also have significant scores... many are worth a pawn, several are >worth way more... ie king safety can be up to +/- 3 pawns or so de- >pending on how exposed and how many pieces are left for the opponent. >Ditto for some endgame things like connected passers on the 6th/7th, or >passer advanced with king support, and so forth. > >Only way I know to tune is play and watch and, if you are a good enough >player, try to figure out where your program went wrong and adjust the >weights to stop that... Hmm. is there any program out there that allows a non-programmer to do stuff like that?
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.