Author: Robert Hyatt
Date: 21:53:30 04/12/03
Go up one level in this thread
On April 12, 2003 at 19:58:09, Uri Blass wrote: >On April 12, 2003 at 19:45:22, Koundinya Veluri wrote: > >>On April 12, 2003 at 06:13:05, Uri Blass wrote: >> >>>On April 12, 2003 at 05:46:08, Jeremiah Penery wrote: >>> >>>>On April 12, 2003 at 04:22:57, Uri Blass wrote: >>>> >>>>>On April 12, 2003 at 01:44:26, Robert Hyatt wrote: >>>>> >>>>>>That has to be part of the evaluation. IE you have to know that you can >>>>>>give the pawn up if your king is closer to the remaining pawns than the >>>>>>opposing king is... >>>>>> >>>>>>I do that obviously... >>>>> >>>>>This has nothing to do with the pawn. >>>>> >>>>>You have to evaluate correctly the following position that can happen >>>>>if you do not search deep enough >>>>> >>>>>[D]8/8/1K6/5p1p/4kP1P/6P1/8/8 w - - 0 6 >>>>> >>>>>I hope that movei will be able to see it after I add some knolwedge but the >>>>>knowledge that is needed is not about passed pawns because there are no passed >>>>>pawns in that position. >>>> >>>>Bob never said anything about passed pawns. >>> >>>He did in the post that started this thread: >>> >>>http://www.talkchess.com/forums/1/message.html?292975 >>> >>>"This seems to be an example of an engine that misses the power of the "distant >>>passed pawn". >>> >>>I agree that a lot of engines have problems in the evaluation but the problem >>>is about not evaluating correctly king relative to the pawns and has nothing to >>>do with evaluation of the "distant passed pawns". >>> >>>Uri >> >>It may take several moves for the white king to capture the passed pawn in some >>variations, so if the search can't see the capture from the initial position, >>then the "king relative to pawns" evaluation might not be sufficient to solve >>this. After the capture is made, the search can usually see the rest faily >>easily so I think the "distant passed pawns" evaluation is more important to >>solve these type of positions. >> >>Koundinya > >I disagree. Disagree all you want, but if you don't evaluate distant passers, you are going to lose so many endings it will not be funny. The king position stuff comes _after_ the passer is created. If you can't evaluate the distant passer, you will never reach the later positions... > >A program without knowledge about distant passed pawns(but with some small bonus >for passed pawns) and with knowledge about king relative to pawns will >have no problem in that position. > >The *only* reason that a program with a bonus for passed pawns can fail here is >lack of knowledge about king relative to the pawns. > >There may be other positions when knowledge about distant passed pawns is >important but not the position that was posted. > >The point is that white has equality without trading rooks and can capture the >black passed pawn without trading the rooks so even a small bonus for passed >pawns is enough to avoid trading rooks unless the search can see that white can >win a pawn after trading rooks and it is exactly what happens to program that >trade the rooks. > >Uri
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