Computer Chess Club Archives


Search

Terms

Messages

Subject: Re: Evaluation-based Reductions and/or Extensions

Author: Vincent Diepeveen

Date: 12:17:13 12/31/03

Go up one level in this thread


On December 28, 2003 at 13:32:05, Tom Likens wrote:

>Hello Everyone,
>
>I've been experimenting recently with using the evaluation function to shape
>the search tree.  Specifically, I've been using the static evaluation of
>the current position and the previous position to determine if a move should
>be extended or reduced.  I also have been making allowances for moves that
>increase or decrease the pressure against the king, attack hung pieces,
>save hung pieces etc.
>
>So far the results have been exciting, but also potentially frustrating.
>The main problem I've encountered is that any pruning or extensions based on
>the previous node's score cause hashing problems because this becomes path
>dependent. In a way, I suppose this isn't much different then making these
>type of decisions based on the value of alpha or beta as well, but these new
>effects have (at least for my program) seemed more detrimental.
>
>My (obvious) question, how do other programmers deal with this phenomenon?

If you want evaluation based selective search, just implement CNS or CNSII
(conspiracy number search). Read some papers from Ulf Lorenz for example.

>I suppose ignoring it is one option, but I'm hoping there is a better
>solution.
>
>regards,
>--tom



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.