Author: J. Wesley Cleveland
Date: 23:35:09 06/08/02
Go up one level in this thread
On June 08, 2002 at 01:02:23, Robert Hyatt wrote: >On June 07, 2002 at 19:44:41, J. Wesley Cleveland wrote: > >>On June 06, 2002 at 20:16:33, Robert Hyatt wrote: >> >>>On June 06, 2002 at 19:24:54, Roy Eassa wrote: >>> >>>>On June 06, 2002 at 19:18:16, Roy Eassa wrote: >>>> >>>>>On June 06, 2002 at 18:02:43, J. Wesley Cleveland wrote: >>>>> >>>>>>On June 06, 2002 at 16:30:19, Roy Eassa wrote: >>>>>> >>>>>>>On June 06, 2002 at 16:25:01, Michael Vox wrote: >>>>>>> >>>>>>>>On June 06, 2002 at 10:10:12, Robert Hyatt wrote: >>>>>>>> >>>>>>>>When Nalimov 32 piece tbs come out someday, it will be over. This will >>>>>>>>eventually happen with stronger hardware. At least every worthy line will be >>>>>>>>saved to dbases. It will no longer be Crafty vs Junior, it will be Crafty dbase >>>>>>>>vs Junior dbase. >>>>>>>> >>>>>>>>No point in discussing computer chess anymore once this level of technology and >>>>>>>>dbases is hit. >>>>>>> >>>>>>> >>>>>>>I hope you're kidding. Even if every atom in the galaxy were used to store 1 >>>>>>>bit of data, that still wouldn't be enough storage for 32-man TBs. (And 100 >>>>>>>billion years wouldn't be enough time to compute them, even on a multi-terahertz >>>>>>>computer.) >>>>>> >>>>>>You are off by a bit. All positions can be stored in ~160 bits, which means that >>>>>>2^160 or 10^48 bits are enough for all TBs. There are more atoms than that in >>>>>>the earth. As to calculation time, we should have fast enough computers in about >>>>>>300 years, if Moore's law holds up. ;) >>>>> >>>>> >>>>>First off, to store tablebases requires more data than just each position >>>>>itself. Second, why did you raise 2 to the power of the number of bits? >>>>> >>>>>How many positions are possible in chess? It's a number with scores of digits, >>>>>and *each* of these entries would require your 160 bits plus more for the other >>>>>required fields (next move, etc.). >>>>> >>>>>And finally, I doubt Moore's Law will hold up for another 300 years! (If >>>>>nothing else, it won't take nearly that long before the laws of physics prevent >>>>>further speedups, at the rate of increase we've been experiencing.) >>>> >>>> >>>>Upon further thought, I understand why you raised 2 to the power of the number >>>>of bits. But does the 160 bits take into account the additional data required >>>>in a tablebase? If not, you need several more bits, which should increase the >>>>final number by orders of magnitude. Plus, I don't think anybody will ever turn >>>>even every tenth atom in the Earth into storage for tablebases... >>> >>> >>>2^160 represents something just below the total number of unique chess >>>positions. >>> >>>Of course, that has _nothing_ to do with solving the game, because path >>>information will be critical with the 50 move rule. >>> >>>In that context, 2^160 words will barely be a start. It might well bu >>>2^160^160 for all I know at that kind of problem... >> >>If you could construct all tablebases up to 32 piece ( a VERY big if), chess >>would be solved and it would fit in the 2^160 or so bits the tables would take. >>It is *quicker* to create tablebases that obey the 50 move rule than tablebases >>that do not. > > >I don't know about the "quicker" part. But the 50-move rule is a serious >problem. It would seem that we need to soon convert to a combination of >DTM/DTC so that we can work around the 50 move rule with some sort of reasonable >algorithm that will work in a running chess engine. > >But in any case, current DTM or DTC by themselves have difficulties that are >serious problems.. If I understand correctly, TBs are generated iteratively one ply at a time starting from mate or conversion until no positions are marked, and all other positions are draws. If you stopped after 100 iterations, you would also have all the positions that could not be won or converted after 50 moves as draws. TBs with pawns would have to be calculated separately for all possible pawn positions, but could be combined later.
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