Author: Paul Byrne
Date: 22:00:37 09/20/03
I read the thread on the pawn game last night... http://www.talkchess.com/forums/1/message.html?316441 ...and added it as a variant to Guildenstern (which is pretty basic as chess engines go, but is set up to handle rules variations like this -- first version took about 10 minutes). The first version called it a win when a pawn hit the 7th rank; changing this to getting a passed pawn more advanced than the opponent's most advanced pawn (passed or not) caused a speedup of about 100x in solving the couple of test positions I was using. Anyways, to give you an idea how solvable this game is or isn't, I left it running on this position last night: [D]8/1pppppp1/8/p6p/P6P/8/1PPPPPP1/8 w - - 0 3 with this result: mv=g4 e=12 d=1 n=14 t=0.000 mv=f4 e=0 d=2 n=104 t=0.000 mv=f4 e=12 d=3 n=371 t=0.002 mv=f4 e=0 d=4 n=870 t=0.002 mv=f4 e=12 d=5 n=2859 t=0.006 mv=f4 e=-7 d=6 n=7296 t=0.013 mv=f4 e=12 d=7 n=17061 t=0.028 mv=f3 e=-4 d=8 n=56297 t=0.128 mv=f4 e=19 d=9 n=152838 t=0.351 mv=f4 e=-7 d=10 n=253530 t=0.586 mv=e4 e=19 d=11 n=718726 t=1.473 mv=e4 e=-2 d=12 n=1169031 t=2.114 mv=e4 e=19 d=13 n=1875217 t=3.137 mv=e4 e=-2 d=14 n=3304028 t=5.235 mv=e4 e=16 d=15 n=6028707 t=9.264 mv=e4 e=0 d=16 n=14889769 t=22.461 mv=e4 e=28 d=17 n=116308613 t=168.791 mv=e4 e=0 d=18 n=277650527 t=400.234 mv=e4 e=27 d=19 n=493734227 t=706.427 mv=e4 e=0 d=20 n=830582334 t=1181.929 mv=e4 e=14 d=21 n=1572079524 t=2209.587 mv=e4 e=0 d=22 n=-989389009 t=4577.107 mv=e4 e=32 d=23 n=1675198974 t=8170.032 mv=e4 e=273 d=24 n=1318190910 t=13610.508 mv=e4 e=9969 d=25 n=-1677339015 t=26967.618 So about 7.5 hours to solve this. I'm sure a program set up especially to solve this would be noticably faster (no need for code for castling, promotion, non-pawn moves, etc, etc) and running on a faster machine than my 1.2 GHz athlon would gain a ply or two. Adding a better eval function would likely aid move ordering some, accounting for the symmetry of the initial position would help, etc. There are plenty of ways to improve on my basic program. I have to suspect the game is solvable -- perhaps not quickly, but not in a totally unreasonable about of time. -paul
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.