Author: Jon Dart
Date: 06:30:37 10/05/99
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On October 05, 1999 at 05:14:23, Bas Hamstra wrote: >(Material - Margin) is a cheap estimation of the current eval. If positional >bonusses get frequently more than a pawn (or even more) "Margin" should be set >to near the maximum the positional part of the score can be, or else this >estimation can become very inaccurate and introduces much errors. Yes. I have a compile-time switch that calculates what the pruning code is assuming the score will be, then goes ahead and computes it. If the score is bigger than the estimate, it prints a warning. > >If positional bonusses get frequently much more than a pawn, maybe it is more >accurate to use this: > > Delta = Alpha - Eval; > >Because with one move the Eval won't change *that* much. Reaction? Depends a lot on what your eval code looks like. For example, I disable qsearch pruning in the endgame, because one small move can create a big change in the score (example: the king moves out of the "square of the pawn" and can no longer catch a passer). If you are clever, you may be able to quickly check for such cases without doing a full eval. --Jon
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