Author: Dave Gomboc
Date: 20:58:35 09/01/99
Go up one level in this thread
On September 01, 1999 at 15:38:44, Robert Hyatt wrote: >On September 01, 1999 at 14:27:37, blass uri wrote: > >>On September 01, 1999 at 09:39:58, Robert Hyatt wrote: >> >>>On September 01, 1999 at 08:49:23, blass uri wrote: >>> >>>>On September 01, 1999 at 07:56:29, Robert Hyatt wrote: >>>>>What is happening here is that Hiarcs is using some unsafe evaluation (IMHO) >>>>>to say that two minors vs one minor is a draw. Rebel lost a game making this >>>>>assumption in the WCCC as Uri pointed out. >>>> >>>>Rebel evaluated KBB vs KN as 0.xx pawns advantage for the BB and not as a draw. >>>> >>>>>I don't call KBN vs KB a draw. Most are. But _all_ are _not_. It makes you >>>>>look like a genius when it is right. And like an idiot when it is wrong. I >>>>>prefer the database approach which is 100% right. >>>> >>>>The problem even with tablebases is with KBN vs KBP >>>>In this case you can go by search for KBN vs KB by sacrificing the pawn but if >>>>you cannot go by search to KBN VS KB your evaluation will be clearly wrong. >>>> >>>>I do not say that the static evaluation should evaluate these positions as draws >>>>but it should evaluate positions of KBN vs KBP as close to a draw and crafty has >>>>not 0.xx evaluations for them. >>>> >>>>Uri >>> >>>It does for safe cases... and it used to for other cases. IE KNN. many programs >>>say the KNN side can't win no matter what. But if the other side has a pawn, >>>it can be a win and they screw up. I let the tablebases handle that one now. >>>There are other cases. As far as rebel, does it matter whether it says +.5 or >>>0.0? It was wrong (seriously wrong) in either case as the two pieces won. And >>>that is the 'unsafeness' I try to avoid. >> >>It is important if Rebel says 0 or 0.5 because if you say 0 for KBB vs KN then >>you may miss an easy draw that you evaluate as 0.00 and if you say 0.5 you can >>not miss an easy draw. >> >>KBB vs KN you can deal with tablebases but you have not tablebases for KBN vs >>KBP so you cannot avoid unsafeness in this case. >> >>Uri > > >correct,although in a tournament game I'll bet the stronger side can win >the pawn with a 3-4 minute search and force a proper evaluation... at least >I did when I tested this with Crafty. > >as far as 0.00 or 0.5, why not -.5 or +5? ie if the number is wrong, it >doesn't matter much as you are getting a wrong score and making a game- >critical decision based on this score. IE the WCCC game. Ed used -0.75 so that it would act as a safety valve against humans (who probably would have a tough time winning KBBKN.) It will be interesting to know if he moves to tablebases for the next Rebel or stays without them. Dave
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