Using material based game state gives a small improvement compared to the move count based one. I only tested it with 400 very high speed games. Most of the games were drawn.hgm wrote:Using the move number, rather than characteristics of the position to determine game phase is a bad idea. Some games proceed quickly, others drag on forever. The same position can be reached in 30 moves in one game, and in 130 moves in another. Even Fairy-Max uses a material-based game state (Q=6, R=3, minor=2, so ranging from 0-40 in orthodox Chess).
End Game Heuristics
Moderator: Ras
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Re: End Game Heuristics
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Re: End Game Heuristics
End game still far from good. Black draws with a mad (rabid) rook. Also white waits far too long with moving its passers. Instead it shuffles its rooks. (3 seconds per move for white so you cannot expect deep searches)
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Re: End Game Heuristics
Rabid Rook is difficult to recognize for engines, so you are a bit unlucky here. (You could divide the score by factor for a branch that ends in a number of checks, but that interferes with hashing.)
It is indeed a bit indecisive before it starts pushing the passer; it seems only to do it opportunistically when black moves away its Rook from behind it, and does not actually make any effort for forcing it forward by covering the square in front of it with one of his Rooks.
Of course this because you don't search deep enough to see the promotion. But even then you should not have this problem if you awarded advancing passers enough. In Fairy-Max a 6th-rank Pawn is worth ~175, and a 7th-rank Pawn ~250. That should help, as on move 74 it would already see an opportunity to gain 75cP by 74. Ra7 Kd4 75. Rh5 any 76. a6 at 5 ply. In fact the whole King chase after move 64 was pointless, allowing the black King to centralize more, which in itself should lower the score. If a more attractive goal, such as getting a Pawn on 6th rank, is in view, it would have opted for that.
It is indeed a bit indecisive before it starts pushing the passer; it seems only to do it opportunistically when black moves away its Rook from behind it, and does not actually make any effort for forcing it forward by covering the square in front of it with one of his Rooks.
Of course this because you don't search deep enough to see the promotion. But even then you should not have this problem if you awarded advancing passers enough. In Fairy-Max a 6th-rank Pawn is worth ~175, and a 7th-rank Pawn ~250. That should help, as on move 74 it would already see an opportunity to gain 75cP by 74. Ra7 Kd4 75. Rh5 any 76. a6 at 5 ply. In fact the whole King chase after move 64 was pointless, allowing the black King to centralize more, which in itself should lower the score. If a more attractive goal, such as getting a Pawn on 6th rank, is in view, it would have opted for that.
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Re: End Game Heuristics
I increased the bonus for 6th- and 7-th rank in piece square table. Quick test showed it helped a bit.hgm wrote:Rabid Rook is difficult to recognize for engines, so you are a bit unlucky here. (You could divide the score by factor for a branch that ends in a number of checks, but that interferes with hashing.)
It is indeed a bit indecisive before it starts pushing the passer; it seems only to do it opportunistically when black moves away its Rook from behind it, and does not actually make any effort for forcing it forward by covering the square in front of it with one of his Rooks.
Of course this because you don't search deep enough to see the promotion. But even then you should not have this problem if you awarded advancing passers enough. In Fairy-Max a 6th-rank Pawn is worth ~175, and a 7th-rank Pawn ~250. That should help, as on move 74 it would already see an opportunity to gain 75cP by 74. Ra7 Kd4 75. Rh5 any 76. a6 at 5 ply. In fact the whole King chase after move 64 was pointless, allowing the black King to centralize more, which in itself should lower the score. If a more attractive goal, such as getting a Pawn on 6th rank, is in view, it would have opted for that.
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- Joined: Mon May 27, 2013 10:31 am
Re: End Game Heuristics
I increased the bonus for 6th- and 7-th rank in piece square table. Quick test showed it was a slight improvement.hgm wrote:Rabid Rook is difficult to recognize for engines, so you are a bit unlucky here. (You could divide the score by factor for a branch that ends in a number of checks, but that interferes with hashing.)
It is indeed a bit indecisive before it starts pushing the passer; it seems only to do it opportunistically when black moves away its Rook from behind it, and does not actually make any effort for forcing it forward by covering the square in front of it with one of his Rooks.
Of course this because you don't search deep enough to see the promotion. But even then you should not have this problem if you awarded advancing passers enough. In Fairy-Max a 6th-rank Pawn is worth ~175, and a 7th-rank Pawn ~250. That should help, as on move 74 it would already see an opportunity to gain 75cP by 74. Ra7 Kd4 75. Rh5 any 76. a6 at 5 ply. In fact the whole King chase after move 64 was pointless, allowing the black King to centralize more, which in itself should lower the score. If a more attractive goal, such as getting a Pawn on 6th rank, is in view, it would have opted for that.