Author: Will Singleton
Date: 19:31:57 09/17/99
Go up one level in this thread
On September 17, 1999 at 12:33:46, KarinsDad wrote: >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 :) So, as I understand it, you are suggesting that the time it takes to generate 2 complete pv's (or more) is less than incorporating a pawn structure eval in a normal (single pv) eval. It would seem to me that in order to get 2 good pv's to the same depth would require twice the time as one pv. Of course, I'm on my second vodka & tonic, so maybe I'm missing something. Will
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