Author: rasjid chan
Date: 11:01:53 04/30/04
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On April 30, 2004 at 07:59:43, Frank Phillips wrote: >On April 30, 2004 at 07:11:02, rasjid chan wrote: > > >> >> But still as others posted, and from theory of alpha-beta that it relies >> only on one signal, ie eval(), evaluation determines how alpha-beta >>searches and the returned best-move. > >Sure, chess is a zero sum game with only three outcomes: 1, 0 or ½. So, unless >the search sees to the end of the game then an evaluation is needed to chose an >end point. I suppose, in fact, to differentiate between all endpoints that are >not won, lost or drawn. I view the evaluation (and chess theory) as a predictor >of the likely outcome of a position for which the end result is unknown. >Sometimes the prediction will be wrong, even with best play. Presumably due to >tactics or wrong or inapplicable theory or the evaluation function being a poor >predictor in the specific case. > >The question then is how much of an evaluation do you need to do well against >the opponents you are likely to play eg to take you to a particular level. >There will always be occasions where the presence of specific knowledge hurts >(over-valuing some positional factors that are not as important as others in >specific positions or vice versa) as will the abscene of specific knowledge in >particular circumstances. > >In theory search or egtbs (the same as search but pre-computed backwards) must >dominate all else. Fortunately chess is still interesting because from a >practical point of view it cannot. Your topic is actually a big ITEM. Another reply here also seem to stress on search, but recent posts seem to indicate even top programmers did'nt exactly give any very definitive answers which I can understand. I have a relevant reply to Uri above. Hope it is not too dumb. > >I doubt there is single set of killer positional elements and their weighting >factors. Nor a single way to arrive at a decent set. And I would repeat that >on a modern cpu a standard search plus any sensible evaluation function should >take you way above 1900. My current program cannot be rated as it is under major changes and some major areas are not proper yet. Thanks. Rasjid
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