Author: Dave Gomboc
Date: 18:00:52 10/22/03
Go up one level in this thread
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
This page took 0 seconds to execute
Last modified: Thu, 15 Apr 21 08:11:13 -0700
Current Computer Chess Club Forums at Talkchess. This site by Sean Mintz.