Author: Stuart Cracraft
Date: 17:41:44 03/06/98
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
This page took 0.02 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.