Author: KarinsDad
Date: 09:33:46 09/17/99
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Robert, A very difficult problem to resolve. Maybe the best solution is to not resolve it heavily at all (i.e. only resolve it to the level you already have or maybe slightly moreso). In my program, I am attempting to make positional moves over tactical moves. So, I have multiple tactically sound PVs which I decide between. One of the criteria that can be used to decide between them is to determine pawn structure at the leaves of each "PV". If you had 30 different pawn structure "ideas" in a database (or hardcoded), you could have a preset evaluation for each of these structures (i.e. 3 white queenside pawns vs. 2 black queenside pawns where the black pawns are doubled is one pawn structure "idea"). You could then use this "evaluation" to positively or negatively affect the decision on which PV to choose (or at least I can do this in my code, you would have to change Crafty drastically to implement this type of model). Hence, if I have 5 PV scores all within 1/8th pawn of each other, I could pick one which SHOULD result in a favorable pawn structure within the next 16 ply as opposed to one which might not. And, the other advantage of this model is that most of this pawn evaluation "stuff" is handled just a few times for each "PV" just before deciding on a move as opposed to within the evaluation code for every node that gets evaluated. Hence, it could be relatively sophisticated (i.e. it could even take into account things such as how advanced the pawns are) and still not take a lot of time. So, the basic idea is to avoid queenside majorities and other endgame weaknesses if possible much earlier in the game. If I have two PVs of similar score, one which should result in a queenside majority for my opponent and one which should not, I pick the one which should not in order to avoid the potential weakness on move 13 as opposed to attempting to evaluate it at move 45. Of course, this type of solution will not work in all positions, but it should emulate better human strategic play as opposed to purely tactical play (i.e. attempt to avoid the pitfalls and cliffs before the position starts heading towards them). Part of the "plan" is to give the program's side the best pawn structure it can way before getting to the endgame. Just an alternative idea. KarinsDad :)
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