Author: Sune Fischer
Date: 16:38:57 01/16/02
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On January 16, 2002 at 13:30:34, Severi Salminen wrote: >>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 LOL, I just gave the exact same answer, that will teach me to read _everything_ in the thread before posting ;) -S.
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