Author: Severi Salminen
Date: 10:30:34 01/16/02
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>It has occurred to me that it is wrong to evaluate a position in terms of >relative pawns (the "de facto" standard - whereby an evaluation of 2 means that >you're approximately the equivalent of 2 pawns ahead). > >This means that many aspects of evaluation have to be squeezed into a dimension >which is not appropriate at all. > >A better way would be to evaluate "winning probability". If a position was a >draw, the value would be 0.50 (or 50%). If the player should win 3 out of 4 >times, the eval should be 75%. If the player must win from here, then the >evaluation should be 100%. > >It seems strange when you think about it that all programmers have chosen to >adopt the traditional "pawn equivalence" standard. Not at all strange. What's the difference if engine sees move A=1.5 pawns and move B=-3.6 panwns, or move A=0.76 and move B=0.06?? And in fact you can change your favorite engine (if source code is available) to scale the score range to anything you want. In my engine matescore is +MAX_INT, which is something like 2'140'000'000, you can divede all score by 2*MAX_INT and then add 0.5, to get the desired range, if it makes you happy (if my sources were available...). Or you can translate it non-linearly (logarithmic or whatever) but the result will be the same: engine pics the move with highest score, no matter if the scale is linear or not. Now we can use a scale we don't have to transale at all: it's fast and clear. Severi
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