Author: Bas Hamstra
Date: 07:40:18 08/12/99
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On August 12, 1999 at 05:58:11, Vincent Diepeveen wrote: >On August 11, 1999 at 21:57:23, Bas Hamstra wrote: > >>This is not a good example of how SEE can error. However there are many examples >>possible. I too think SEE can miss things, like all sorts of pins and throw out >>captures when it shouldn't. However, as a percentage of all captures, how often >>does that happen? I think there is consensus that the errors are more than >>compensated by the reduction of qnodes. > >There is no consensus about this at all. > >I'm the opposite. It's like the real dumb program Bob and i are >discussing about, in the end those stupid things will lose as tactics >aren't the weakest chain in chessprograms. > >If you use SEE for SURE your eval is the weakest chain. You con't even >see exchanges correctly, or you grab poisened pawns. > >A SEE cannot be combined with a big evaluation. A see works brilliant >for piece square table programs though, as junior quite obviously shows, >as they don't lose knowledge when applying it. > >>A cheap alternative is to throw captures out when after a capture the capturing >>piece is hanging (and A > D). > >>Regards, >>Bas Hamstra. >> >> >> >>On August 11, 1999 at 16:12:07, Tom King wrote: >> >>>I must be missing something obvious with using SEE to prune >>>in the Q. search. If I understand right, "losing" captures >>>(according to the SEE) are pruned right out. But I fail to >>>see how this won't screw up big time. >>> >>>Let's take an example. Now assume we have a white bishop on G5 >>>and a black knight on F6, and the knight is protected by a pawn on G7. >>>Now the SEE might well assume that BxN is a loser (assuming that >>>the bishop is worth a fraction more than the knight), because >>>after BxN, gxB, white has lost a bishop for a knight. But it >>>might be that this is in fact a very good capture, because it >>>destroys black's kingside. And a program with the SEE Q. pruning >>>might not want to play this? Am I missing something obvious >>>here? >>> >>>Cheers >>>Tom
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