Computer Chess Club Archives


Search

Terms

Messages

Subject: Re: MINMAX verses ALPHA-BETA

Author: Larry Griffiths

Date: 11:54:56 01/20/99

Go up one level in this thread


J., Robert, and Karinsdad,

Thank you for your replys.

I disabled some extension code and was able to get the AB and the
Minmax only to produce the same scores and moves.
I will look at the extension code and try to figure out where
my thinking has gone south.

I want to be able to do extensions when a king is in check or
on captures since I do not have a swap-off routine in the
scoring function.  I am trying to overcome some of the
nastyness of the horizon effect by going deeper on captures.
Example:

Black has a Bishop on A8, a Pawn on B7, and a Rook on B8.
White has a Queen on A1.
(forget about Kings in this example).

With Black to move and using a depth of two plys,
Any move by Black will be responded to by White with
the Queen capturing the Bishop on A8.
It appears that White has won a Bishop but at three plys
Black sees that the rook must stay on the 8th rank to
protect the bishop and capture the Queen should white
venture such a foolish move.

The example above is clear to me but things seem
to get much more complex at deeper plys.

Are there any good articles on Selective Extensions and how to
handle the horizion effect? (Besides NULL moves).

Thanks!





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.