Author: Randall Jouett
Date: 20:41:51 05/26/02
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On May 26, 2002 at 18:15:41, Robert Hyatt wrote: Howdy Bob, >I have said this before, I will say it again. Bitboards are mathematically >provable to be just as good as any other chess board representation. Think >about it for a minute and you will understand why. There is nothing you can >do with your offset (mailbox) board representation that I can't do with >bitboards, and vice-versa... I agree with this statement. I guess the real question is this: Has anyone ever bothered to compare the number of cycles it takes to represent things using bitboards and indexing? Off the top of my head, I would have to say that, with a 64-bit processor, the bit-board method could win out, especially if there are a bunch of registers that happen to be hanging around for use :^). IMHO, the really important thing here, no matter which method is used, is to keep things on chip as often as possible. Fetching things from memory is time consuming :^). OTOH, putting setting up a pointer to an array and placing this pointer (address) into a register is pretty quick, too, and not only that, but the code is pretty simple. With all of this in mind, I would think that hash tables (i.e., not having to re-evaluate the tree) and good heuristics in EvaluatePosition() are where the true benifits would lay. In other words, I think we'd all much rather have a great heuristic that was slow that a bad heuristic that was fast :^). Anywho, IMHO, I think the argument is kinda moot until we all sit back and actually start counting cycles, folks :^). I haven't bothered doing this myself, but I think we could easily write a simple bit-board engine and an indexed-array engine and settle this once and for all time. Well, maybe settle this until with start seeing photonic processors or something. Who knows what other kinds of advancements we'll see by then? :^) Best Regards, NOP -- Randall Jouett Amateur Radio: AB5NI I eat spaghetti code out of a bit bucket while sitting at a hash table!
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