Author: Peter McKenzie
Date: 17:52:01 05/02/00
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On May 02, 2000 at 20:35:09, William Bryant wrote: >In my program my killer table is simply an array of [ply][2] with two killers >allowed per ply. When updating the killer table, I replace the first killer >with the new one (assuming it is not the same move), and move the old first >killer to the second killer position, dropping what ever move is in the second >killer position. > >In the introductory paragraphs of Ernst's book, he describes using counters >to order the killer moves (page 23) >"The killer moves carry "hit" counters with them which specify their priorities >for sorting and replacement." > >This would, of course, require a larger table, and more time spent updating >and sorting the killer table. > >Is this more efficient or effective than a standard replace table? Other >thoughts or comments about organizing the killer moves? My program has 2 killers, with counts. If a new killer is found, I replace the killer with the lowest count. If a killer move is found that is one of the 2 in the list, I just update its count. I guess this is also the scheme that Ernst was referring to, its pretty simple to implement and seems to work OK. I don't use the counts for move ordering at all, if a move is found that matches either killer it gets the same bonus added to its move ordering score. Perhaps I should try making the bonus slightly bigger for the killer with the biggest count... Some time ago (months? years?) there was a huge debate on CCC (or was it rgcc) about killers, and whether the counts were worth while. I can't remember the exact conclusion, but from memory it varied from program to program. So as usual, suck it and see :-) > >Thanks. > >William >wbryant@ix.netcom.com
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