Author: GeoffW
Date: 16:14:19 09/02/04
Go up one level in this thread
Hello Bob Thanks the good explanation, that made sense. Ross and I don't increment ply when we Null move which explains the discrepancy I think. It seems like that is wrong and we should do, except my stupid program doesn't want to play ball and is going splat after having I changed it. Yet another bug to go hunting for ! Regards Geoff >OK. we search a move at ply=1, a move at ply=2, and a move at ply=3. When we >get to ply=4 I try a null-move. I go to ply=5 and try a move that just happens >to mate my opponent. But I don't notice here. I then advance to ply=6 and try >all moves and discover there are no legal moves. The side to move is in check, >with no legal moves, which is checkmate. I return MATE-6 to ply=5 which is >happy with that. Ply=5 returns MATE-6 to ply=4 where I do the test. At ply=4 >now that test becomes > >(remember value = -(MATE-6) here due to negamax and at the moment ply=4) > > > >if (value == -MATE + ply + 2) > > if (-(MATE-6) == -MATE +4 +2) mate_threat = 1; > if (-MATE+6 == -MATE+6) and that is true. > > >> >>The thing I cant decide now is have I implemented this correctly without a bug ? >>From my results it seems that it could be correct, but the search explosion is >>very bad at deeper ply (compared to Bobs quoted figures ) >>Maybe the threat extension code is OK, but just highlighting my poor move >>ordering ? >> >>Any thoughts would be appreciated >> >>here are my results >> >> >>check extensions, but no mate threat extensions >> >>Ply Eval Time Nodes Principle Variation >> 9 -151 606 5753869 g2f1 e8c8 c1b1 f4d5 h1g1 d6f4 b3d5 d7d5 f1e1 >>10+ -106 1456 14387871 g2f1 >>10+ 194 2910 29451052 g2f1 g8f8 h4h5 g6h5 h1h5 e8e1 f1e1 f4h5 c1h6 f8e8 >>h6h8 d6f8 h8h5 f8b4 e1d1 >>10 9989 4514 49522394 c1f4 d6f4 h4h5 g6h5 h1h5 f4h6 h5h6 c7h2 h6h2 g8f8 >>h2h8 >> >>Computer's move: c1f4 >> >> >>check extensions, and mate threat extensions >> 6 -210 10 106899 g2f1 a7a5 f6e5 f4d3 c1g5 d3e5 d4e5 d6e5 g5g6 >> 7 -203 48 462385 g2f1 e8e2 c1b1 d6e7 h4f4 c7f4 f1e2 f4f6 >> 8+ -158 214 2114011 g2f1 e8e2 c1b1 e2d2 f6g5 d2d4 g5f4 d6f4 b1g6 >> 8+ 142 237 2343262 c1f4 >> 8 94 290 2904048 c1f4 e8e6 h4h5 g6h5 f4g5 g8f8 b3e6 f7e6 g5h5 >> 9+ 139 337 3307392 c1f4 >> 9+ 439 521 5024678 c1f4 >> 9 462 810 7874059 c1f4 e8e6 f4g5 d6e7 b3e6 e7f6 g5g6 f6g7 e6b3 a7a5 >>g6h5 d7d4 h4d4 g7d4 >>10+ 507 1128 10950029 c1f4 >>10+ 807 1945 19089764 c1f4 >>10 9989 10639 144085366 c1f4 d6f4 h4h5 g6h5 h1h5 f4h6 h5h6 c7g3 g2g3 a7a5 >>h6h8 >> >>Computer's move: c1f4 >> >> Geoff
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