Author: Antonio Dieguez
Date: 12:16:00 10/15/99
Go up one level in this thread
On October 15, 1999 at 15:02:05, Robert Hyatt wrote: ... >>>>>What do others do? >>>> >>>>(In the root I sort moves according to their scores, which doesn't take >>>> much time anyway.) >>>> >>>>Elsewhere: In move generation I give a number of priority for each generated >>>>move. e.g. if pawn captures queen, its priority is 1, non-captures priority >>>>is 7 and so on... Then in search routine I have a loop I:=1 to 7 and I >>>>try in the first round the moves of priority 1, then those of priority 2etc. >>>>So I don't have to sort the moves. >>>> >>>> Jari >>> >>>that is still an N^2 algorithm, as you make N passes over N moves. Unless you >>>get an early cutoff. This is called a 'selection sort' and is the way I order >>>the non-captures in crafty. I try 4 passes thru the 'selection sort' taking >>>the best history score each time. After 4 passes, I quit the selection sort >>>and take the moves in the order they were generated, as it has become very >>>likely that this is an ALL node and there will be no cutoff anyway. This turns >>>the N^2 algorithm into a 4N algorithm which when N=40+, is significantly faster. >> >>why did you say N passes over N moves? a pass is a round or a loop right? if I >>understood what Jari told, there are only 7, or not? (what a coincidence I do 7 >>rounds too!) >> >>bye bye... >> >>me. > > >No.. he makes a pass over the entire move list to pick the move with the >highest 'priority'. Then the next time he wants a move, he does this again. >One pass per move is the only way I can see to do it unless they are actually >sorted by priority first, which is a waste of cpu cycles... but he has only 7 level prioritis, or he said another thing? well, another question, is good to maintain 1 killer capture? I think yes... who maintains a killer capture? me. (the prince of amy mizuno, sailor mercury.)
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