Author: Robert Hyatt
Date: 12:17:37 10/09/98
Go up one level in this thread
On October 09, 1998 at 10:37:29, blass uri wrote: > >On October 09, 1998 at 10:25:28, blass uri wrote: > >> >>On October 09, 1998 at 09:56:20, blass uri wrote: >> >>> >>>On October 09, 1998 at 09:35:55, Robert Hyatt wrote: >>> >>>>On October 09, 1998 at 08:54:02, blass uri wrote: >>>> >>>>> >>>>>On October 09, 1998 at 08:10:51, blass uri wrote: >>>>> >>>>>>I think it is better to store the number of moves to win in the tablebases only >>>>>>if this number is divisible by 2 because otherwise you can compute the number of >>>>>>moves by search. >>>>>> >>>>>>Maybe it is possible practically to store it only if it is divisble by 3 or 4 (I >>>>>>do not know what is the speed of reading the tablebases from harddisk) >>>>>> >>>>>>Uri >>>>>I think it is easy to save at least 1 bit per position by this idea if in >>>>>positions when there is win in N when N is divisible by 2 you store win in N/2 >>>>>and in positions when there is a win in N when N is not divisible by 2 you store >>>>>a win in 1(you can discover by search that it is not truth). >>>>> >>>> >>>> >>>>this is imposible to do. KNN vs KP is a mate in over 100 moves. How do >>>>I separate mate in 50 from mate in 100? I certainly can't search to find >>>>this out... >>> >>>I mean that when you store the number N/2 you mean win in N >>> >>>you have only to search 2 plies because if you have mate in 99 >>mate in 99 is not a good example because of the 50 move rule but >>I understand that there is a problem here because the opponent may do a move >>that let you only to do mates in an odd number of moves so 2 plies cannot help >> >>Uri > > >you can store mate in N by the number N/2 or N-1/2 and find by search the right >move >you need all the time to decrease the number >I think that you have to compute sometimes 4 plies forward but if you fast >enough in reading the tablebases then it can help > >Uri > > I probe the databases in 20 ply searches, so that isn't a problem... but what if *all* probes say "mate in 40"... but some are really mates in 41... how do I *ever* force it to get to mate in 39, when it can, purely by luck, follow the mate in 41 moves forever... > >> >>>the tablebases will tell you the number 1 >>>You know by search that there is no mate in 2 but you have in the tablebase >>>mates in 98 so by searching 2 plies you can read from the tablebases the mate >>>in 98 after 2 plies. >>>Searching 2 plies and reading the tablebases after every 2 possible plies(you do >>>not need every 2 possible because of the alpha beta is not impossible >>>> >>>> >>>> >>>>>By this idea you can use the same number of bits to every position. >>>>> >>>>>If you want to use different number of bits to every popsition you must add 1 >>>>>bit >>>>>to tell if the is a position with win in number of moves divisible by 2 or not. >>>>> >>>>>of course if you lose it is not important to know the number of moves. >>>>> >>>>>I use the word win and not mate because it is a mistake to use mate >>>>>because of the 50 move rule >>>>> >>>>>Uri >>>> >>>> >>>>distance to conversion has the same 50-move problem... >>> >>>why? >>>If the distance is more than 50 then you know it is a draw. >>> >>>Uri
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