Author: Dann Corbit
Date: 12:30:27 12/12/05
Go up one level in this thread
On December 12, 2005 at 15:24:08, Greg Simpson wrote: >On December 12, 2005 at 14:52:05, Dann Corbit wrote: > >>On December 12, 2005 at 14:39:20, Álvaro Begué wrote: >> >>>On December 12, 2005 at 14:07:17, Dann Corbit wrote: >>> >>>>On December 12, 2005 at 14:01:45, James Constance wrote: >>>> >>>>>When a tablebase says that a position is a win in more than 50 moves does it >>>>>take into a account the 50 move rule i.e. that a piece has been taken or a pawn >>>>>moved? >>>> >>>>No. But it's trivial to count it yourself. >>> >>>It's not that trivial. If your database gives distance-to-mate values, it is in >>>possible in principle that it will spend over 50 moves without making a pawn >>>move or a capture, which results in a draw. A good database should know about >>>distance to an irreversible winning move, and consider anything with a distance >>>over 50 to be a draw. Then you can try to win faster if you want. I don't know >>>if any tablebases currently available do this correctly, but in practice it will >>>probably not matter. >> >>It will multiply the size of the database by a very large number. >>You follow your projected pv to the end result. If you do not win, but only >>draw, you were not going to win anyway. So there is not value at all to adding >>the 50 move rule and a huge cost associated with it. >> >>e.p. is another matter and one that could have more importance, I think. >>It's not inconceivable to let a pawn sit for almost the full game (especially a >>king shelter pawn). > >But the tablebases in search are used to find trades that will lead to a winning >endgame. If the tablebase is showing a line that leads to a 50 move draw as a >win, it could be chosen even though not trading down immediately could lead to a > win later. I am not sure that I see the problem. If my move counter is 30 and I see a mate in 99-30+1 by lookup, then I better check the pv. I guess that you could write piggy-back EGTB that have already done the math. I would only check all the way to the finish for my mainline pv.
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