Author: Greg Simpson
Date: 12:24:08 12/12/05
Go up one level in this thread
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.
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