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Subject: Re: Branching factor, etc

Author: Omid David

Date: 11:33:08 08/30/02

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On August 30, 2002 at 14:27:53, Andreas Herrmann wrote:

>On August 30, 2002 at 09:56:21, Omid David wrote:
>
>>On August 29, 2002 at 23:03:43, Dann Corbit wrote:
>>
>>>On August 29, 2002 at 22:50:53, Brian Richardson wrote:
>>>[snip]
>>>>Is move sorting turned off in Yace, GLC and Gnu for the depth = 6 searchs?
>>>
>>>Pretty irrelevant since all of them show a branching factor between 2 and 3 for
>>>the opening position.
>>>
>>>The program described by the OP had a branching factor of 6-8, IIRC.
>>>
>>>IOW, something is clearly amiss.
>>>
>>>I wonder how often the OP finds the requested position in the hash table.
>>>Usually, hash table alone would be enough to prevent a branch factor that
>>>terrible.
>>
>>How do you calculate branching factor here?
>
>A branching factor of 3 means that each node has in the average 3 child nodes
>(This is the description i have found on an internet page). So the formula must
>be:
>
>bf = ( Nodes [ply n] - nodes [ply n-1] ) / nodes [ply n-1]
>
>Excample:
>Whole nodes until ply 5 = 4000 and whole nodes until ply 6 = 20000.
>Then you got a branching factor of
>bf [ply 6] = ( 20000 - 4000 ) / 4000 = 4.0
>
>have a nice day
>Andreas

I know this :-)

But there is the odd/even issue, so the b-factor can change drastically while
moving from an odd ply to an even ply, and vice versa.



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