Author: Tom Kerrigan
Date: 14:57:30 05/30/00
Go up one level in this thread
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
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