Author: Robert Hyatt
Date: 12:35:07 03/31/03
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On March 31, 2003 at 15:20:35, Martin Giepmans wrote: >On March 31, 2003 at 14:35:48, Uri Blass wrote: > >>Today latest movei evaluates passed pawns and protected passed pawns based on >>the ranks of the pawn(I will later change it to evaluate them >>based on other factors like square of the kings). >> >>The problem is that the order of evaluation is not correct. >> >>If I have a pawn at b5 and another passed pawn at c5 then >>I want to evaluate them as better than pawn at b4 and >>protected passed pawn at c5. >> >>I thought to give a bonus for passed pawn that has pawn in the left side of it >>but the problem is that in that case the evaluation is not >>symmetric and in the folowing diagram if the black pawn is in c6 and not f6 >>I get different result. > >I think giving bonus/2 if there is a pawn on the right OR on the left side >would do the trick. It's symmetrical. Does this imply that one passed pawn is as good as two? Not in my book. :) > >> >> >>[D]8/7k/5p2/8/3PP3/8/8/K7 w - - 0 1 >> >> >>Another problem is what to do when there are 3 passed pawns. >> >>[D]8/7k/8/8/3PPP2/8/8/K7 w - - 0 1 >> >>In that case even if I decide to give only one bonus for pair >>I may get here 2 bonuses and after the central pawn progress >>one square forward I will have only one bonus. >> >>I wonder how other programs solve that problem. >> >>protected passed pawns are good but other things are also good and the problem >>is how to order the things in the right order. >> >>Uri > >In my engine I give a bonus for a passed pawn that is >(a) protected by a pawn (left or right) >or >(b) has a pawn on the left or on the right I do those separately. a bonus for connected, which is separate from a pawn that is protected. Note that connected is worse when there are _no_ pieces on the board, so that needs to be factored in. > >If both are not true (pawn is not protected and has no neighbor) I give a >small penalty. The penalty is so small that it will not hinder the advance >of the passed pawns. But it helps the engine to keep it's pawns "together". > >Cheers, >Martin
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