Author: Anthony Cozzie
Date: 18:34:31 10/22/03
Go up one level in this thread
On October 22, 2003 at 21:00:52, Dave Gomboc wrote: >On October 22, 2003 at 14:40:23, Uri Blass wrote: > >>On October 22, 2003 at 13:13:37, Vincent Diepeveen wrote: >> >>>On October 22, 2003 at 06:30:13, Sergei S. Markoff wrote: >>> >>>>Hello All! >>>> >>>>DS - is a term for using some features of classical evaluation that consists of >>>>two parts - material and positional. >>>>There are a lot of positions in that for one side material evaluation is >0 but >>>>positional evaluation is <0 or vice versa. The root of big part of mistakes made >>>>by modern engines is underestimating of positional eval because the positional >>>>evaluation is constructed of several "atomic" factors. The _sum_ of this factors >>>>frequently isn't good positional evaluation (anyway there are a lot of >>>>"palliative" methods to avoid this problem like evaluation the relationship >>>>between several factors). We can't fully trust positional evaluation and that's >>>>why most of modern programs using a small values for a lot of factors. >>> >>>In 1990 your statement would have been true. >>> >>>However in 2003, i know very little modern programs with small values for the >>>positional factors. Perhaps diep is one of them in some sense, yet the quantity >>>makes the total positional score overrule any material reality. >>> >>>>The idea of DS is to use disagreement between positional and material >>>>evaluation. There are a lot of ways how to use it. For example we can check >>>>nodes in which sum_eval < alpha, but positional eval is large (for example we >>>>sacrificed a pawn for attack e.t.c.). For this nodes we can: >>>>1. Rebuild quiescence to include checks e.t.c. >>>>2. Extend search >>>>3. Change eval for the case of losing pawn or quality (trade bishop or knight >>>>for rook) for big passed pawn / king attack eval. >>>>4. Do assymetric eval. >>>>5. Something else? >>>> >>>>Do you have some ideas in this area? >>> >>>In case you forgot, the evaluation can just return 1 score and that's a total >>>score it can't return 2 scores for either positional or tactical matters. >> >>I do not think that sergei forgot something. >>He is a good programmer and smarthink is one of the best free engines. >> >>The fact that the evaluation can return only one score does not mean that the >>program cannot compute more than one score to get decisions because decisions >>are not only about evaluation but also about which lines to extend. >> >>Uri > >There's no law that says a score must be scalar. > >Dave I just had a vision of a program that returned tensors in its eval. Hmm. I'm with Sergei on this one though - Zappa already keeps track of the various "parts" of the eval, so I can tell if the position has a high kingsafety score for white or some such. anthony
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