Author: scott farrell
Date: 18:30:16 01/08/04
I know there was a huge thread about the array being 32, I think it might only need 4. I also didnt read that howle thread, so someone can just tell me if you came to this conclusion already. Given the rules of what is in crafty: - minimax outcome - LVA - fixed ordering, must always use smallest first - king can take, and is scored as mate (or thereabouts if you capture) - currently crafty goes through all attackers, until on side has none, it uses a 32 sized array to hold capture values, that are built up, and then minimaxed now that maximum score returned than can be minimaxed, is the whole piece you are capturing, any more and it will be minimaxed away. the minimum score is the piece being captured, less the attacking piece, anything less will be minimaxed away. I hope the 2 statements above are sound. The next part of my argument is I think you only 3-4 entries in the array, and you dont need to iterate all pieces, just the first 1 or 2 captures each (depending how you count them - and if you count the first one or not). after the initial capture, the other side either has a good capture, or they dont. To determine if there is a good capture or not, I dont see that we need to pile a nearly unlmited number of pieces on. The minimax could would need a slight tweak to disregard the last capture I think. if we have a position that starts of pawn x pawn, we dont need to minimax through all the RxR and RxR QxR QxQ KXQ stuff to work out that somewhere adding in more captures will always be minimaxed away. I need to think more on exactly the maximum number of captures is required, but I am sure it is way less than 32, no matter what is on the board. So I am saying instead of exhausting the captures for one side, make an early exit after a maximum of 2 captures each - or some other similar small number. Or I could be completely wrong. I might try coding it up both ways, and see if the answer ever differs. Scott
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