Author: Uri Blass
Date: 02:15:45 01/21/02
Go up one level in this thread
On January 21, 2002 at 04:10:06, David Rasmussen wrote: >On January 20, 2002 at 18:24:33, Uri Blass wrote: > >>On January 20, 2002 at 16:39:23, David Rasmussen wrote: >> >>>On January 20, 2002 at 14:36:44, Uri Blass wrote: >>> >>>> >>>>but it is still not clear because the other evaluation stuff is important. >>>> >>> >>>Of course the other evaluation stuff is important. I am not suggesting to cancel >>>all evaluation other than material. I am just saying, instead of having a pawn >>>be 1 and a knight be 3, and then somewhere in evaluation check if you have >>>exchanged a knight for three pawns, then you penalize by, say, 0.5, why not just >>>let the knight have a value of 3.5? I know there are more than one requirement, >>>which is why it isn't trvial. But there still might be a solution. It is >>>basically a linear programming problem. I don't say that material values should >>>cover all sorts of evaluation cases, but material _do_ have values right? And >>>who says that 1,3,3,5,9 is the Unchangeable Truth? >> >>I did not say that 1 3 3 5 9 is the unchangable truth. >> >>I said that the numbers are meaningless without more knowledge about the >>evaluation. >> >>1 3 3 5 9 in a chess program may be eqvivalent to 0.8 3 3 5 9 if you change the >>piece square tables. >> >> >>Uri > >This has nothing to do with piece square tables. I am _only_ taking about >material special cases. Three pawns for a bishop. Two minor pieces for a rook >and a pawn. Two rooks for a queen. Etc. Everything else will still have to be in >the evaluation. The reason for having material values in the first place is >_primarily_ to solve such _material_ special cases. Is it good to win a queen >for a pawn? Yes, 1,3,3,5,9 says it is. Is it good to win two minor pieces for a >rook and a pawn? 1,3,3,5,9 says it doesn't matter. 1,3.5,3.5,5.5,10 says it's a >good idea. If the minor pieces had little mobility, and the rook was active it >might be a bad idea. Other evaluation terms will measure that. But you will have >to have these terms _anyway_. Why have 1,3,3,5,9 and then have code that checks >if you have traded two minor pieces for rook and pawn and then give a penalty? > >/David You assume that material is evaluated as a constant and positional evaluation is added later It is not the case in my program I have a constant array for evaluating white pieces int pcsq[6][64] When I need to evaluate a knight at b2 I simply translate knight to 1 I translate b2 to 9 and I add pcsq[1][9] to my evaluation. Can you tell me based on the array pscq[6][64] what is the value of the knight in my program? Uri
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