Author: Robert Hyatt
Date: 19:22:24 12/08/00
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On December 08, 2000 at 20:41:40, Landon Rabern wrote: >On December 08, 2000 at 16:16:01, Robert Hyatt wrote: > >>On December 08, 2000 at 13:21:21, Peter Fendrich wrote: >> >>>On December 08, 2000 at 13:06:43, Robert Hyatt wrote: >>> >>>>On December 08, 2000 at 12:56:09, Peter Fendrich wrote: >>>> >>>>>I looking for a measurement for move generation performance. >>>>> >>>>>Do you think FH/CountNodes, where FH is number of times the first generated move >>>>>was a Fail High, is a good measurement? >>>>>Do you have some other? >>>>>What's your figures? >>>>>I get some 50% and I have a feeling it's to low. >>>>> >>>>>//Peter >>>> >>>> >>>>The critical statistic I measure in crafty is this: "For any position where >>>>I 'fail high' (return a score >= beta) what percentage of the time does it >>>>happen on the _first_ move?" I generally average 92%. Anything over 90% is >>>>reasonable. Anything less means move ordering needs work. >>> >>>OK, it seems logical. I have in princple 3 types of FH: >>> 1) Hash table (without moving) >>> 2) Null Move >>> 3) Ordinary moves (including the hash table move) >>> >>>Do you include all these cases? >>>With only the third case counted I'm well over 90% >>> >>>//Peter >> >> >>Only 1 and 3. 2 is done at a different place in the search and doesn't >>really count in "move ordering". >> >>Actually, the way you wrote it, only 3 counts. for 1) you are not searching >>a move, so that can't be counted. 2) doesn't count either... > >I am getting about 80% on this, is this real bad? I am not doing internal >interative deepening, do you think this will help a lot, or do you think there >is something else wrong. > >I try moves in this order: > >hash/pv >all captures sorted MVV/LVA >two killers >3 history scan moves >the rest > > >Regards, > >Landon W. Rabern Your MVV/LVA ordering is probably the culprit. Because you are trying moves like QxP, even though the pawn is defended... and you try those _before_ you try the move that will ultimately fail high (a killer or history move). I would still expect it to be higher than 80%... but that might be about right with MVV/LVA. You get some of that back in terms of faster ordering, and you get some back because the bad captures get cut off quickly by null-move searches... but it could be better...
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