Author: David Rasmussen
Date: 01:04:53 01/21/02
Go up one level in this thread
On January 21, 2002 at 02:00:29, Robin Smith wrote: > >In the general case, two rooks are considered stronger than a queen, not >weaker. Of course there are always the many exceptions, for example the queen >is beter at picking off numerous weak isolated pawns, but in general Q>2*R is >not correct. Also Queen is usually more or less equal to 3 minor pieces, not >greater. > >>>>>So maybe P=1, N=3.2, B=3.4, R=6, Q=13? > >Q=11 would be a beter choice. 13 is way too high. > >Also, Euwe's formula of 1,3.5,3.5,5.5,10 is much better than the classic >1,3,3,5,9. > Wow. That is what I use. And I came up with it myself. And I'm no Euwe... >>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 > >This is all elimentary algebra. Just write 5 equations for the 5 unknowns >(values for P, N, B, R, Q) and solve. One possible solution: > I know. I stated that elsewhere in the thread. It is a LP problem. >If you assume: >P=1 >N=B >R+2P=2N >N=4P >Q+P=2R > >Then solving yields the result: > >P=1 >N=4 >B=4 >R=6 >Q=11 > >Different, perhaps more complex equations will give different results. And none >will be completely satisfactory .... there are too many exceptions. > >Robin I would make equations. I would make inequalities, and solve the LP model. There are several sets of values that will work, and what one chooses in the end depends on what other evaluation you have. But you can certainly catch more special cases with Euwe's numbers than with 1,3,3,5,9. /David
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.