Author: leonid
Date: 04:11:10 02/08/00
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On February 08, 2000 at 03:31:31, KarinsDad wrote: >On February 07, 2000 at 21:02:39, leonid wrote: > >[snip] >> >>Thanks for explanation! Was very curious for me to see your way of writing the >>logic and impress me by its difference. >> >>I don't use the bitboard or look up table. Everything goes after stright and >>"simple logic" that we usually use in all kind of games. It could be that your >>way is more efficent. >> >>Leonid. > >Who can tell? > >One thing I do to speed it up is to calculate all of the main bitboards (white >and black rows, columns, and diagonals) from the previous position's bitboards. >This means that I only have to figure out how the start location of a piece move >affects the bitboards (i.e. clears a bit in 4 bytes) and how the end location of >a piece move affects the bitboards (i.e. sets a bit in 4 bytes and clears a bit >in 4 bytes for the other color). Note: an EP move is slightly different, it >affects the bitboards by clearing the bit of the pawn being captured (in 4 >bitboards) in a different location in the other color bitboards. > >I haven't profiled this, but I think it is a significant savings over taking >every piece and setting a bit in 4 bitboards as to it's location. > >KarinsDad :) All your way to put the logic going is so different that I must one day look into it. In this moment I am not in programming. In my logic I do not differenciate the capture against "empty moves". This is done only after the generation of all the moves for given position. Exception is only one ply where I have special move generator that find only "capture". Probably you use some efficent way where you can generate one move at once and immidiately try it. I never could see how to do this beside one ply. I am forced to find all the moves for the ply in order to aline that later in best way possible. After all, general data needed to recognize the legality of each move is found in advance for entire ply. From where is the strange result - less efficent is my logic (forced to see more moves for each ply) better the nodes per second rate it provide. Leonid.
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