Author: Stefano Gemma
Date: 01:51:39 07/24/04
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On July 23, 2004 at 18:33:36, Gerd Isenberg wrote: >Is your getNextMove O(N**2)? [...] To avoid moving data forth and back from the memory, i've tried two approach. The first one, since my old Drago and Raffaela, was to search the next move, without ordering the moves (we have already talked about this, in this forum, some year ago). A simple variation to this approach is to store the best move generated, as the first move to try (this is done directly by the move generator). Then we search the next best move, any time we need it. This could be expensive, if you're near the root, because the most of the moves are always played, but is helpfull when you're near the leaves, beacause the most of the moves were pruned away. The second way i've tryed for getNextMove, in the new engine Freccia, is... not to store the moves at all!!! It seems very strange, if you don't store the moves, how can you find the best one? I've considered that, with my move generator, i need from 2 to 4 assembly istruction, to know if a move is legal. If i store the legal moves, i need some extra 3 or 4 assembly istruction to save piece and delta (i use 0x88 like chessboard rappresentation). After stored the moves, i need to have a loop that search the best one. I can avoid this loop, because i need only 2 istruction, to know if a move is legal, why to store the move itself? I can just add the test for the best one in the move generator, without to store the moves (except the best one or the its index). This stuff works well, but it is almost impossible to implement in a satisfactory way, when you implement Iterative Deepening, because you need somewhere to store the value returned from ID iteration and associate it to the right move. In the nodes far from the root, it is tremendously efficient, but just for nodes where you need only one move to prune. I'm experimenting on a mixed approach, but i'm a little busy with my work, since ten years ;-) Ciao!!! Stefano Gemma
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