Author: Tom Likens
Date: 19:27:57 09/23/04
Go up one level in this thread
On September 23, 2004 at 16:58:33, Roman Hartmann wrote:
>hello all,
>
>while testing my move generator (10x12 array, only legal moves) and comparing
>the perft result from Crafty and my own results I noticed that my results differ
>for some positions a bit. As the results start to differ only at some depth it's
>not that easy to track this bug. Although I'm quite certain that the problem is
>somehow related to EP-moves I wasn't able to solve this riddle yet.
>
>By searching the web I found some websites with perft results from other chess
>engines with numbers even more off than the results from my move generator.
>
>some results -total nodes- from my move generator (proper Results from Crafty):
>rnbqkbnr/pppppppp/8/8/8/8/PPPPPPPP/RNBQKBNR w KQkq - 0 1
>perft 4: 20603 ok
>perft 5: 5072212 ok
>perft 6: 124132506 (124132536) differ
>
>r3k2r/p1ppqpb1/bn2pnp1/3PN3/1p2P3/2N2Q1p/PPPBBPPP/R3K2R w KQkq -
>perft 3: 99949 ok
>perft 4: 4185800 (4185552) differ
>perft 5: 197909832 (197876242) differ
>
>8/2p5/3p4/KP5r/1R3p1k/8/4P1P1/8 w - -
>perft 3: 3017 ok
>perft 4: 46264 (46255) differ
>perft 5: 720964 (720879) differ
>perft 6: 11761790 (11750962) differ
>
>8/PPP4k/8/8/8/8/4Kppp/8 w - -
>perft 5: 1840260 ok
>perft 6: 36177037 ok
>
>Well, as searching for this bug has allready consumed much more time than I ever
>expected it would I'm not sure -after having seen this sites- that the the move
>generator has to be perfect in order to create a working chess engine. On the
>other hand my move generating process is quite complicated and I'm not sure if I
>will still understand all the parts of it in a few months like I do understand
>them now.
>
>What should I do about that? Try to track down this bug at any price or just go
>on an do some work on other parts of the engine and fix this bug later? Or
>should I just forget about the bug at all?
>Thanks for all suggestions in advance.
>
>Best regards
>Roman
Hello Roman,
You should probably fix the bug, if you don't this will bite you when you
enter your first major computer chess tournament and you're playing Shredder
for the championship of the world. To help I've included the output from
my chess program Djinn for your 2nd and 3rd positions, (if you're interested
you can download the engine at):
http://webpages.charter.net/tlikens
Anyway, here's the output for the positions mentioned above.
==========
POSITION 2
==========
r3k2r/p1ppqpb1/bn2pnp1/3PN3/1p2P3/2N2Q1p/PPPBBPPP/R3K2R w KQkq - 0 1
WHITE<1> perft -v 5
Total number of moves for depth 1: 48
White Black
===== =====
NORMAL 36 0
CAPTURE 8 0
ENPASSANT 0 0
PROMOTION 0 0
PCAPTURE 0 0
CASTLED_KS 1 0
CASTLED_QS 1 0
PAWN_JUMP 2 0
Total number of moves for depth 2: 2039
White Black
===== =====
NORMAL 0 1549
CAPTURE 0 350
ENPASSANT 0 1
PROMOTION 0 0
PCAPTURE 0 0
CASTLED_KS 0 46
CASTLED_QS 0 45
PAWN_JUMP 0 48
Total number of moves for depth 3: 97862
White Black
===== =====
NORMAL 73452 0
CAPTURE 17057 0
ENPASSANT 45 0
PROMOTION 0 0
PCAPTURE 0 0
CASTLED_KS 1625 0
CASTLED_QS 1537 0
PAWN_JUMP 4146 0
Total number of moves for depth 4: 4085603
White Black
===== =====
NORMAL 0 3078017
CAPTURE 0 747402
ENPASSANT 0 1929
PROMOTION 0 7340
PCAPTURE 0 7832
CASTLED_KS 0 62119
CASTLED_QS 0 65894
PAWN_JUMP 0 115070
Total number of moves for depth 5: 193690690
White Black
===== =====
NORMAL 145297283 0
CAPTURE 34967567 0
ENPASSANT 73365 0
PROMOTION 5908 0
PCAPTURE 2484 0
CASTLED_KS 2624637 0
CASTLED_QS 2369000 0
PAWN_JUMP 8350446 0
Depth Peft(depth) Total Nodes
----- ----------- -----------
1 48 48
2 2039 2087
3 97862 99949
4 4085603 4185552
5 193690690 197876242
==========
POSITION 3
==========
8/2p5/3p4/KP5r/1R3p1k/8/4P1P1/8 w - - 0 1
WHITE<1> perft -v 6
Total number of moves for depth 1: 14
White Black
===== =====
NORMAL 11 0
CAPTURE 1 0
ENPASSANT 0 0
PROMOTION 0 0
PCAPTURE 0 0
CASTLED_KS 0 0
CASTLED_QS 0 0
PAWN_JUMP 2 0
Total number of moves for depth 2: 191
White Black
===== =====
NORMAL 0 165
CAPTURE 0 14
ENPASSANT 0 0
PROMOTION 0 0
PCAPTURE 0 0
CASTLED_KS 0 0
CASTLED_QS 0 0
PAWN_JUMP 0 12
Total number of moves for depth 3: 2812
White Black
===== =====
NORMAL 2326 0
CAPTURE 207 0
ENPASSANT 2 0
PROMOTION 0 0
PCAPTURE 0 0
CASTLED_KS 0 0
CASTLED_QS 0 0
PAWN_JUMP 277 0
Total number of moves for depth 4: 43238
White Black
===== =====
NORMAL 0 37886
CAPTURE 0 3225
ENPASSANT 0 123
PROMOTION 0 0
PCAPTURE 0 0
CASTLED_KS 0 0
CASTLED_QS 0 0
PAWN_JUMP 0 2004
Total number of moves for depth 5: 674624
White Black
===== =====
NORMAL 570042 0
CAPTURE 50886 0
ENPASSANT 1165 0
PROMOTION 0 0
PCAPTURE 0 0
CASTLED_KS 0 0
CASTLED_QS 0 0
PAWN_JUMP 52531 0
Total number of moves for depth 6: 11030083
White Black
===== =====
NORMAL 0 9650914
CAPTURE 0 906585
ENPASSANT 0 33325
PROMOTION 0 7112
PCAPTURE 0 440
CASTLED_KS 0 0
CASTLED_QS 0 0
PAWN_JUMP 0 431707
Depth Peft(depth) Total Nodes
----- ----------- -----------
1 14 14
2 191 205
3 2812 3017
4 43238 46255
5 674624 720879
6 11030083 11750962
best of luck,
--tom
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