Author: Charles Roberson
Date: 14:41:54 01/04/06
I've never seen this theory stated before, if anyone in any of the science
communities has then I want the reference. If anyone has similar experience or
sees a flaw in my logic, lets hear it.
Is it possible for an improvement in search depth to result in a performance
degradation in match play.
I am thinking yes! The implication is interesting. You improve the search of
your engine. That is the only change. It now searches two ply deeper. But in
match play it scores worse. Your natural thought was that all else was the same
thus you've a bug in your search improvement.
I think it is possible to improve the search and get worse results. Here is
how.
Lets say that your position evaluator (PE) is out of tune on some
strategic/positional values. Deeper search works with the PE to create an edge
for your program. Your old search was keep pace (depth) with opponents, but the
new search sees two ply deeper on average. This gives your engine increased
opportunity to create an edge. Once the edge is realized, the engine is in a bad
position and the match is lost.
Before it couldn't create the edge because it couldn't tactically out see
the opponents. Seems to me this scenario only happens when the PE is not
extremely out of tune, but is somewhat close to in tune.
So, can increases in search depth in match play cause an out of tune PE to
reveal its issues.
This seems to be happening in some my tests today. Other data my program
(prior) to the changes has a propensisty for getting into good opening and
middle game positions and then blowing it. Thus, increases in search depth may
allow it to see an advantageous postion (in its thoughts (PE)) and go for it at
earlier moves in the game. Also, increasing its chances of realizing those
positions. Thus, producing worse play.
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