Author: Uri Blass
Date: 15:10:37 09/06/02
Go up one level in this thread
On September 06, 2002 at 17:59:15, Dann Corbit wrote: >On September 06, 2002 at 17:45:15, Uri Blass wrote: > >>On September 06, 2002 at 15:46:53, Tony Werten wrote: >> >>>On September 06, 2002 at 14:45:11, Dann Corbit wrote: >>> >>>>Did anyone notice his cutoff idea in the evaluation function? >>>> >>>>It seems to me to be a very good idea, and I don't know if others have tried it >>>>out. >>>> >>>>Basically, it consists of three modes with two early exits... >>>> >>>>1. If the material + structure score alone is dominant enough, it exits right >>>>away. >>>>2. Otherwise, it processes the piece list. If that score is dominant, it exits. >>>>3. Otherwise, it does a full board control scan for all 64 squares. >>>> >>>>It is described starting on page 62 under the section "3.3.2 Multi Staged >>>>Design" >>>>He gets roughly 71% evals returning in stage #1, 13% in stage #2 and 7% in stage >>>>#3. >>>> >>>>It seems like it might be a big win to do it that way. >>> >>>It's called lazy eval and is not a good idea. The times it is wrong happen to be >>>the important ones. >>> >>>Tony >> >>I use incremental evaluation. >>The only cases when I can be wrong in being lazy is in my qsearch because I do >>not make every stupid capture in my qsearch. >> >>Example: >>Suppose I search the position after >>1.e4 e6 2.Bb5 a6 as the root position and have a score of 0.0 pawns at depth 2. >> >>If I search 3.c4 axb5 and goto qsearch then I do not make the move 4.cxb5 >>inspite of the fact that with possible high positional scores I cannot be sure >>that the positional score after 4.cxb5 is not high enough to justify that move. > >I am curious to know how your qsearch knows which captures to attempt and which >to ignore. I have a score for the evaluation of the position and I calculate the estimated score for the change in the evaluation after the capture. The sum of these numbers is the estimated evaluation after the capture and I use this number to decide if to ignore or not to ignore the capture in the qsearch. Uri
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.