Author: Uri Blass
Date: 11:36:44 01/20/02
Go up one level in this thread
On January 20, 2002 at 10:25:50, David Rasmussen wrote: >On January 20, 2002 at 10:12:28, Uri Blass wrote: > >>On January 20, 2002 at 09:41:48, David Rasmussen wrote: >> >>>On January 20, 2002 at 09:29:24, Severi Salminen wrote: >>> >>>>On January 20, 2002 at 09:01:50, David Rasmussen wrote: >>>> >>>>>There must be a value system of material that takes care of all special cases. >>>>> >>>>>1,3,3,5,9: >>>>> >>>>>Has the following problems: >>>>>3 pawns for bishop or knight is almost always a bad idea. >>>>>2 knights/bishops for rook and pawn is almost always a bad idea. >>>>>2 rooks for queen is often not a good idea. >>>>>3 knights/bishops for a queens is often not a good idea. Then again, often it is >>>>>:) >>>>> >>>>>What is your best bet? >>>> >>>>And sometimes a Bishop is better than a knight. So: >>>> >>>>P=1, B>N>3*P, R+P>2*B, Q>2*R and Q>3*B. >>>> >>>>So maybe P=1, N=3.2, B=3.4, R=6, Q=13? >>>> >>>>Severi >>> >>>I don't want to score bishop higher than knight. It depends on dynamic factors >>>that should be in evaluation anyway. I just want to avoid extra code to evaluate >>>special cases, as Crafty does. I think it is possible. >>> >>>/David >> >>There is no answer for your questions. >> >>It is even not possible to know what is the meaning of P=1 >>because the value of the pawn is dependent in the square of the pawn. >> >>If you do not use piece square table for pawns then your program may be weak >> >>If you use piece square table for pawns than P=1 is eqvivalent to P=1.2 when you >>only change the piece square table for the pawns. >> >>Uri > >Look, I am not talking about perfect evaluation here. I am talking about a >mature evaluation function, but instead of evaluating material special cases >(three pawns for a bishope etc.) as crafty does, I think all of these _material_ >special cases can be done with material values alone. All the other evaluation >stuff will still be there. > >/David but it is still not clear because the other evaluation stuff is important. If you have pawn value of 0.8 and piece square table that says: 0 for 2th rank 0.05 for 3th rank 0.10 for 4th rank 0.20 for 5th rank 0.40 for 6th rank 0.70 for 7th rank It is the same as having pawn value of 1 and piece square table of -0.2 for the 2th rank -0.15 for the 3th rank -0.1 for the 4th rank 0 for the 5th rank 0.2 for the 6th rank 0.5 for the 7th rank Uri
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