Author: Tom Kerrigan
Date: 15:58:11 05/30/00
Go up one level in this thread
On May 30, 2000 at 18:01:31, Robert Hyatt wrote: >On May 30, 2000 at 17:57:30, Tom Kerrigan wrote: > >>On May 30, 2000 at 17:24:29, Gian-Carlo Pascutto wrote: >> >>>On May 30, 2000 at 14:54:28, Tom Kerrigan wrote: >>> >>>>I assume that when Bob says he expects a 25% hit rate, he means 25% of the >times that the hash table is probed, and not 25% of the nodes. >>> >>>Probably yes, so did I... >>> >>>>Which means that more work needs to be done to estimate the speedup from the >optimization that started this thread, i.e., the equation becomes: >>>> >>>>speedup = (% hit rate) * (% hash probes) * (% hash move cutoffs) * (% of time >>>>spent doing move generation) >>>> >>>>Throwing in some extremely optimal numbers, the result is: >>>> >>>>0.5 * 0.2 * 0.5 * 0.2 = 1% >>>> >>>>So I think the best you can hope for is 1%. Seems like too much work for too >>>>little, to me. >>> >>>If you do the same optimization for killer moves, how much can you hope for >>>then ? >>> >>>This would be (killer move cutoffs) * (time doing move generation), right ? >>> >>>The second term is pretty high for me, so I'm interested to know what the >>>first one will be. Anybody got any numbers on this ? >>> >>>-- >>>GCP >> >>Depends on how you generate moves... >> >>Captures should be ordered higher than killers, so you have to generate >>captures. For me, if you're generating captures, you might as well generate all >>the moves while you're at it. >> >>Don't forget, there's also some overhead in bypassing move generation. You have >>to keep track of which "stage" of move generation you're in. You have to make >>sure you don't search the same move twice. And you have to test the legality of >>hash and killer moves. Basically, this is overhead on an improvement that's >>already small. Not worth it, in my opinion... >> >>-Tom > > >It definitely works for me... What improvement does it give you? -Tom
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