Computer Chess Club Archives


Search

Terms

Messages

Subject: Re: Research idea? re: weight optimization

Author: Wylie Garvin

Date: 10:05:34 12/30/01

Go up one level in this thread


On December 29, 2001 at 05:11:26, Tom Kerrigan wrote:

>Here's my idea.
>
>You have a position and you want your program to play a certain move (which it
>presumably isn't playing). You run this algorithm:
>
>1. Search the position, get a PV. The evaluation of the last position of the PV
>is eval(1).
>2. Search only the move that you want your program to make, get a PV. This
>end-point evaluation is eval(2).
>3. Figure out which eval terms are different between eval(1) and eval(2).
>Decrease the weights of all the different eval(1) terms slightly. Increase the
>eval(2) terms slightly.
>4. Repeat until the program plays the move you want.
>
>You could run this on lots of positions from GM games, to get your program to
>play like a GM. (At least in some positions, heh.)
>
>Has this been done before? Are there any glaring problems with this idea? Does
>anybody want to try this? If so, I'd like some credit for it. If not, I'll
>probably get around to trying it sometime...
>
>-Tom

Hi Tom,

  A lot of people have replied already, but just in case no one has mentioned it
you should check out Baxter et. al.'s TDLeaf() algorithm.

TDLeaf(): Combining Temporal Difference Learning with Game-Tree Search
http://citeseer.nj.nec.com/139694.html

  They trained their program's eval function automatically on a large set of
grandmaster games.  I did some fooling around with this once with my AI prof,
his idea was, rather than adjust the evaluation incrementally, to collect a long
list of constraints (one for each position in which the program would play
the "wrong" move) and then simultaneously solve as many of the constraints as
possible.  But we didn't pursue it too far because it turned out that Baxter et.
al. had made a few clever optimizations in their program (I think it was
KnightCap they were working with, if I remember right) which gave it most of the
benefits of optimizing globally.

Wylie



This page took 0.01 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.