Author: Moritz Berger
Date: 07:17:51 05/31/98
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On May 30, 1998 at 18:36:51, Christophe Theron wrote: >>>On May 29, 1998 at 14:52:42, Christophe Theron wrote: >>>>>BS2830-14: >>>>>r1bqr1k1/pp1n1ppp/5b2/4N1B1/3p3P/8/PPPQ1PP1/2K1RB1R w - - 0 0 bm Nxf7 >>>>> >>>>>BT2630-09: >>>>>r5k1/pp2p1bp/6p1/n1p1P3/2qP1NP1/2PQB3/P5PP/R4K2 b - - 0 0 bm g5 >>>>Tiger does not find the first position in a reasonnable time (it >>>>evaluates Nxf7 as being slighty inferior as the moves it would play). >>>> >>>>On the second position, the result is (computer is K5-100MHz): >>>> >>>>With 0.5Mb hash table: g5 found in 127.10s >>>>With 1Mb : 114.52s (9.90% faster) >>>>With 2Mb : 108.36s (5.38% faster) >>>>With 4Mb : 101.06s (6.74% faster) >>>>With 8Mb : 96.77s (4.25% faster) >>>>With 16Mb : 91.50s (5.45% faster) >>>>With 32Mb : 88.37s (3.42% faster) >>>> >>>> >>>>It is obvious that the table gets quickly filled when I give Tiger only >>>>0.5Mb hash. I think it is getting full only at the end of the search >>>>with 32Mb hash tables. >>>> >>>>The only thing that is obvious is that more hash brings less and less >>>>speedup. There is always something to gain from more hash tables, but >>>>not much when you already have, say, 16Mb. >>>> >Okay. Every program is different. > >My point is only that Fritz hash tables behaviour is not very different >from other programs behaviour. I chose mine to give an example, but you >can find similar data with other programs too. > >Speculation would be to pretend that Fritz has such a different >behaviour. > >But Fritz manual seems to have created a kind of legend around this. It >is just time to calm down and to realize that there is nothing special >to talk about. > Chess Tiger gets a 12% speedup on the two positions mentioned above by going from 4MB hash tables to 32MB. Fritz gets 23% on the 35 positions in the LCT II testsuite from a roughly 4-fold hash table increase from 12MB to 98MB (on P233MMX hardware). I therefore feel that the hash table efficience issue for Fritz could well be somewhat different from e.g. your program or Crafty. Moritz
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