Author: Filip Tvrzsky
Date: 05:22:10 06/22/02
Go up one level in this thread
On June 21, 2002 at 23:23:41, Robert Hyatt wrote: >On June 21, 2002 at 23:05:25, Filip Tvrzsky wrote: > >>Let me suppose my solution of your problems with hashed matescores (quite simple >>and in fact identical with that of Mr. Hyatt): adjust the evaluation every time >>just after you become it from the depth "depthroot + 1". >>Something like: >> int Evaluation = -Alfabeta(-Beta, -Alfa, Horisont_alfabeta - 1); >> if (Evaluation < -MATVALUE + 100) Evaluation++; >> else if (Evaluation > MATVALUE - 100) Evaluation--; >>Of course, when the side to move is mated, you should return evaluation >>"-MATVALUE". >>And that is all! Then you do not need care for it more when hashing or using >>hash values. I use this solution in my chess program now (I had also big >>problems this kind for a long time) and it works fine! >>Sorry for my poor English. >>Filip Tvrzsky > > >That looks problematic. alpha/beta values will be wrong, if I understand >what you are saying correctly. That ought to make the search wildly unstable >in a position with _lots_ of mates in various numbers of moves. Of course, you are right ... I have forgotten to add the second part of this solution - I adjust Alfa/Beta values immediately after enter in Alfabeta function: incrementing them when they are greater then MATVALUE - 100 and, vice versa, decrementing when < -MATVALUE + 100. I hope now it is really all. I am sorry, but it was 5.00 a. m. local time, when I was writing my message ...
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.