Author: blass uri
Date: 12:24:22 10/09/98
Go up one level in this thread
On October 09, 1998 at 15:20:01, Robert Hyatt wrote: >On October 09, 1998 at 11:58:37, blass uri wrote: > >> >>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 >> >> >>of course I mean (N-1)/2 iand not N-1/2 >>I choose N/2 if N is even and (N-1)/2 if N is odd >>if 2 plies search are not enough than 4 plies are enough >>the number of times you should call the tablebases if you have a good order of >>moves is something like 1000 >>I do not know the time that you need for it >> >>Uri >> >> > > >Near the root of the tree, you are right. But imagine a position from the >root where the best you can do is mate in 40. And there are some mate in 41 >positions out there too. I can *never* search deeply enough to actually see >those mates without tablebase hits, and all I get from the tablebase for either >type of move is "mate in 40". If I follow toward the "mate in 41" because the >scores are identical, the next search I will again have the same problem, >because it will still be a mate in 40, but I might choose the mate in 41 since >the scores are the same... > >I don't see a way around this... The point is that you search to find score that is not identical mate in 40 and mate in 41 are the same score but mate in 39 is better and you can find by search of 4 plies mate in 39 If you cannot improve the score by search of 2 plies you improve it by search of 4 plies Uri > >> 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 >>> >>> >>> >>>> >>>>>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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