Author: Stuart Cracraft
Date: 12:13:04 09/11/04
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On September 11, 2004 at 15:03:33, Michael Henderson wrote: >On September 11, 2004 at 14:49:41, Stuart Cracraft wrote: > >>On September 11, 2004 at 12:13:36, Sune Fischer wrote: >> >>>On September 11, 2004 at 00:08:20, Stuart Cracraft wrote: >>> >>>>Hi, >>>> >>>>I added keeping a triangular pv in main search and quiescence >>>>to compare it with the output of my walk-the-hashtable-pv. >>>> >>>>The two differ frequently but quite often are also mostly >>>>identical all the way through. >>> >>>Don't forget to check the hash flag, that the moves are actually PV moves. >>> >>>Mostly you get them overwritten with upper or lower moves, those should not go >>>in the PV. >>> >>>>Which should I trust? Seems like the hash table is getting >>>>overwritten with other variations (not sure why). What >>>>kind of scenario would cause that? My algorithm is >>>>length >= depth to replace. >>> >>>That's not a very good replacement scheme, if you only have a single bin I'd >>>recommend using replace always. >> >>This gave a nice improvement on a Thinkpad laptop of 237 solved of WAC >>@ 1 second per, to 244. >> >>I guess recency is more important than depth!!! I don't know why I never >>even considered to replace always. Didn't even test it. I always had >>assumed that depth was more important than recency. Bad assumption >> >>Nowadays, do most use 2-tier or ? If so or whatever, what are the preferred >>replacement algorithms? >> >>Thanks, >>Stuart > >Recency is important for short searches in which the average depth is small -- >not much overwriting. Using always replace or depth >= depth exclusively in >tournament games will restrict your depth in many situations. Most use both (2 >tables)--I tested it vs other implementations and I found it's the best. > >good luck, >Michael Ah, good call. Perhaps make the algorithm dependent upon how much target time for the search or the average depth being searched so far, etc.
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