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Subject: Tree Searching help

Author: Mark Taylor

Date: 08:37:52 02/21/00


Can anyone help me with a tree searching problem? I am about to start my first
chess program soon, and have a question from working on my checkers program
over the last 10 years.

The problem is that when the static evaluation was passed back up the tree, it
hardly changed the behaviour of the program, because the tree search showed that
that benefit could usually be gained "later" - so "good"  moves did not get
played until the opponent was about to steal the advantage, then the program
would play the "right move"  just in time!

An idea I had was to have a small incrmental value subtracted from the eval,
this small increment getting larger the deeper into the tree search the eval was
returned from. I had already done this for the values WON & LOST, but I
hesitated doing it for positional evaluation because a) it seemed a debugging
nightmar; and b) it didn't seem correct "penalising" an eval the deeper search
it was returned from - intuitively deeper searches are to be trusted more than
shallow searches.

What I did in the end I made the first search iteration look at positional eval
& material eval, then subsequent iterations looked at material eval only - but
this was really a cop out.

What do other people do?

Thanks,
Mark.



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