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Subject: Re: Please, say in few words what can reduce the "branching factor".

Author: KarinsDad

Date: 12:22:16 09/20/99

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On September 20, 1999 at 14:47:49, leonid wrote:

[snip]
>
>My engin: 6 plys 0.22 sec.    8 plys 18 sec.     10 plys 14min. and 54 sec.
>
>Rebel 10:        2.6 sec             40 sec              12min. and 8 sec.
>
>If my "branching factor" between 6 plys and 8 is 82, for Rebel it is only
>15.3. This is how Rebel take over on the 10 ply. Number of positions per
>second are almost indentical but my are higher. Average number of nodes
>per ply is 36.
>

Well, it appears that the branching factor for your program (2 ply) from ply 8
to 10 is 49.7 whereas Rebel's is 18.2. So, your branching factor from ply 8 to
ply 10 is dropping relative to your branching factor from ply 6 to ply 8. Rebel
on the other hand has a slightly increasing branching factor from ply 8 to ply
10 relative to it's ply 6 to ply 8.

So, whatever the problem is, it does appear to be based on the position (i.e.
some set of positions give you a much greater branching factor relative to Rebel
than another set 2 ply higher). Since pure Alpha Beta should have a ballpark of
a 2 ply branching factor of 36 for the position you are examining, I would guess
that you have a mistake somewhere in that portion of the algorithm. Maybe
assigning Beta to a bound when you should assign Alpha or something along those
lines.

KarinsDad :)





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