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Subject: Re: Branch factor

Author: Jaime Benito de Valle Ruiz

Date: 08:33:49 07/25/03

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On July 25, 2003 at 08:35:17, Mridul Muralidharan wrote:

>Hi,
>
>  How exactly is the branch factor being calculated in your programs ?
>Is there any "standard" ?
>
>Thanks and Regards
>Mridul

I don't really know how this is usually calculated (and I'm curious), by you can
try this and see what you get:
It is assumed that the branching factor in chess is 35 as an average. This makes
little sense, because the mean average can not be applied to a non-linear
function such as an exponential one. You have 35 nodes for the first ply, 35x35
for the second, 35^3 for the third... etc. The problem is that you don't get
exactly 35 every time, so all this is just an approximate model.
However, if you want a kind of "average" branching factor (let's called B), then
you should have B nodes for the first ply, B^2 for the second,... B^(ply) for
any ply.
Therefore, if you have for example 36,719,000 nodes at depth 12, then your
branching factor to the power of 12 should be 36,719,000. So:

  B=ROOT(12, 36719000)

  or

  B=36719000^(1/12)       ( = 4.27 in this example)

Well, if this makes little or no sense, just ignore it.
Regards



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