Author: Komputer Korner
Date: 22:46:32 05/30/98
Go up one level in this thread
On May 30, 1998 at 18:36:51, Christophe Theron wrote: >On May 29, 1998 at 15:35:54, Komputer Korner wrote: > >>On May 29, 1998 at 15:10:43, Mark Young wrote: >> >>>On May 29, 1998 at 14:52:42, Christophe Theron wrote: >>> >>>>On May 29, 1998 at 06:04:42, Enrique Irazoqui wrote: >>>> >>>>>On May 29, 1998 at 01:23:32, Christophe Theron wrote: >>>>> >>>>>>On May 28, 1998 at 20:01:08, Enrique Irazoqui wrote: >>>>>> >>>>>>> >>>>>>>On a PII/300 >>>>>>> 100MB 50MB 25MB >>>>>>>BS2830-14 208'' 224'' 301'' >>>>>>>BT2630-09 404'' 406'' 435'' >>>>>>> >>>>>>> >>>>>>>On a P200MMX >>>>>>> 100MB 40MB 22MB >>>>>>>BT2630-09 524'' 560'' >>>>>>>Fritzmark 174 156 154 >>>>>>> >>>>>>>Chessbase claim that by increasing hashtables from 40 MB to 100 MB on a >>>>>>>P200MMX, Fritz 5 is 50 Elo points stronger. It doesn't make sense to me >>>>>>>that doubling RAM has the same effect as doubling the processor speed. >>>>>>>After the times above, maybe going from 25 to 100 MB hash Friz 5 can >>>>>>>become some 20 points stronger. >>>>>>> >>>>>>>Enrique >>>>>> >>>>>>Thanks for the concrete data, Enrique. >>>>>> >>>>>>So we can see on these positions that Fritz gains 31% in speed on >>>>>>BS2830-14, and 7% on BT2630-09 when we give it 4x times more hash >>>>>>tables. >>>>>> >>>>>>Could you please post the positions in EPD format, so I will be able to >>>>>>give the results for Tiger as promised? >>>>>> >>>>>> >>>>>> Christophe >>>>> >>>>>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 >>>>> >>>>>It's true that many more positions are needed to make sure about the >>>>>influence of hash size on Fritz 5, but I am too lazy to collect so much >>>>>data. I picked 2 positions where F5 uses an amount of time typical of >>>>>games at 40/2. >>>>> >>>>>Enrique >>>> >>>>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. >>>> >>>>But it is hard to say by looking at the numbers that the search suddenly >>>>slows down because of a full table. >>>> >>>>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. >>>> >>>>This is true for Tiger, and one could object that Fritz behaves >>>>differently, which still has to be shown. >>>> >>>>If Fritz gets the same percentage speedup when you double its hash >>>>tables than other programs, and that's what I believe, then it is not >>>>clear to me why Fritz is considered as an exception regarding hash table >>>>management and needs... >>>> >>>I found the same results with fritz 5. See Fritz5 (fritzmark profile). >>>Fritz is not an exception. Like your program more hash does help some. >>>But less and less as you add more hash. So I don't see a big ratings >>>gain going from 50 mb to 100 mb for Fritz 5 as some people may think. >>> >>> >>> >>>>How is it that we hear so much about Fritz5 and nothing about, say, >>>>Virtual Chess, which is an underestimated great program? Should I >>>>remember you which is the current world champion amongst the >>>>professional microcomputer programs? >>>> >>>> >>>> Christophe >> >>Because hash tables store previously calculated positions and because >>they fill up with limited time and because the replacement strategy is >>slightly different depending on the program/position and because each >>program has a different implementation of the hashing function (vis a >>vis 2 tables vs 1 table ; pawn hash tables...etc) and because each >>program has different move ordering algorithms, and because every >>program has different search strategies, you cannot say a priori that >>all programs are equally affected by larger hash tables. Of course you >>need a table as large as one move's worth of thinking will store, but >>when that is not possible based on the thinking time and the speed of >>your computer, then the search will slow down by the same factor as the >>hash table enabled it to speed up. The search will not grind to a halt >>nor will the slowdown be that much but in the endgame it can be more >>than a factor of 2. Tests are needed for every program playing every >>other program in matches at different hash table sizes ( one match where >>the hash table never fills and one match without hash tables). Until >>these tests are completed and I wonder if they will ever be given the >>fact that different programs are optimized for different arhitectures ( >>Intel vs AMD) , this argument will remain just speculation, given the >>amount of rancor and difficulty of conducting regular matches in the >>first place. > >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. > > > Christophe I agree. Fritz 5 is such a fast searcher on new fast computers that it needs much larger hash tables so that it doesn't need to use it's replacement strategy on time controls such as 40/2. Until computers come with lots and lots of RAM, this argument will keep going in circles. I fear the RAM capacities will never keep up with the increase in hardware speeds.
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