Author: blass uri
Date: 23:03:49 10/11/98
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On October 11, 1998 at 10:35:41, Robert Hyatt wrote: >On October 11, 1998 at 03:27:59, blass uri wrote: > >> >>On October 11, 1998 at 00:17:55, Robert Hyatt wrote: >> >>>On October 10, 1998 at 14:51:56, blass uri wrote: >>> >>>>I think it is possible to save space by storing only win,draw,loss in these >>>>tablebases >>>>when you go to the position with 4 pieces you can generate the tablebase >>>> >>>>Maybe it is not practical for blitz but it can be practical for tournament time >>>>control. >>>> >>>>Uri >>> >>>I would not want to generate either KBNK or KQKR on the fly... because >>>I probe *in* the search, and need the result then, not just at the root. >> >>You will have the result because I did not say not o have the result of >>win/draw/loss >>>And KQKR can't be built in a couple of minutes by anybody yet... the 3-4 >>>piece files take 3-4 *hours* to build, in total... >> >>It is not important to build all the 3-4 pieces files but only the KQKR when you >>get to the KQKR endgame and you can save it in the ram and not in the harddisk >>so you are faster. >> >>I read that before some years(I think in 1989 but I am not sure) a 6 pieces file >>was generated by a computer by 6 hours and it found mate in more than 200 in a >>position of KRBvKNN or something similiar(it was done by a super computer andnot >>by a personal computer but personal computers are today better) >> > > >this was done, but on a 50 million dollar computer. Which is not going to >be available to any of us in a tournament... nor will the PC catch up to >the speed of that machine for 20-30 years... So there's no use planning on >being able to compute even a 5 piece file. IE KRP KR takes 80 hours plus >on a machine faster than a PC today (big alpha machine). You also need to >compute the promotion classes which take 12-24 hours each to build. You need to compute the distance to conversion for 24 KRPvKR There are 24 possible places of the pawn(I do not count files e,f,g,h) It should not be more than 24 time slower than KQvKR if you know all the sons. The number of positions is bigger because you cannot use symmetric consideration when there is a pawn but the number of moves per position is smaller than KQvKR and the maximal number of moves before conversion is lower. Do the 80 hours on big alpha machine including generating the sons? I think that building KRvKN or KRvKB is faster then KQvKR The complexity of the problem is : (number of positions *Number of moves per position*maximal number of plies to force a conversion) How much time do the best pc need to build these tablebases and How much time they need to generate a move(can I save time if I save in the ram all the possible moves for every possible position)? I think it can be done if you have 256Mbytes ram. Uri
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