Author: scott farrell
Date: 01:26:50 12/03/02
I choose to start the story now ...
A few months ago I added code to show "mate in 4" rather than just mate. It uses
mate-depthTree in order to document the mate depth.
This helped alot in actually mating opponents, as it can choose the shortest
route to mate. rather than as it was just doing lots of checks, that all lead to
mate, and randomly actually mating the opponent.
This worked well, EXCEPT, in deep checking lines, it actually fails slower, as
it tries to look for a better mate. So it actually blew nodes out somewhat on
some test positions.
I still go a few more plies during iterative deepening to try to find shorter
mates - due to null move and pruning etc. But these searches seem to be slow
also.
I recently added a nice piece of code:
if (alpha>INFINITY/2){
matein= INFINTY-alpha; //or whatever you use to calc mate depth in plies
if (depthTree>matein)
return alpha;
}
Do others think this is valid? fail low if you are already too deep, and just
fail low.
It sure verifies the mates about 1000 times faster.
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Last modified: Thu, 15 Apr 21 08:11:13 -0700
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