Author: blass uri
Date: 04:37:56 05/02/00
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On May 02, 2000 at 06:26:34, Michael Neish wrote: > >Hello, > >I wonder whether anyone could help me, or offer any suggestions as to the >following little problem. > >The program I'm writing needs two ply to see what I think should take only one >ply. > >In the position below White wins material by the blindingly obvious Bg5. > >[D]6k1/pp1nrppp/5rb1/P2P4/5BP1/5P2/4BK1P/R3R3 w - - > >However, if I set my program to look only one ply deep, it doesn't see this >move, and prefers Bb5. At two ply, though, it sees it all right. I think one >ply should be enough, as the Qsearch ought to take care of the ensuing >exchanges. Indeed, other programs I have tried manage to find it easily enough >in one ply. I agree that it is possible to see it in one ply but part of the other programs like crafty and Fritz cannot see it in 1 ply. How do you want to see it in 1 ply? One way is to give the position after Bg5 positive static aevaluation because of the fact that your evaluation function knows that one black rook will be probably captured(In this case your evaluation may be sometimes wrong when the rook can escape and threat mate but the evaluation is always sometimes wrong and I think that seeing it by evaluation is a better evaluation function when the price is that you will be slower in nodes/second). It is also possible to see it by extensions if you do not stop at positions when one piece is under threat. simple Qsearch with no extensions is not enough to see it in 1 ply because you need to search 2 non capture moves before the first capture. Uri
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