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Subject: Re: Novice question on reporting of ply count

Author: Robert Hyatt

Date: 09:08:38 02/04/05

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On February 04, 2005 at 10:32:19, S J J wrote:

>On February 04, 2005 at 10:18:36, Robert Hyatt wrote:
>
>>On February 04, 2005 at 06:43:24, S J J wrote:
>>
>>>When a program reports a ply count, is it the number of ply that have the moves
>>>100% generated without pruning, or the deepest node that is checked with
>>>extensions, or something different?
>>>
>>>Steve
>>
>>
>>Depends on the program.  Generally accepted practice is to report the number of
>>plies searched full-width not counting extensions or q-search.  Some programs
>>(such as Junior) use "ply" in a different way which can be misleading if you
>>compare plies between two programs.
>
>  Thanks Robert.   If you assume a branch factor of 30, does that
>mean that a program that reports a 12 ply search had generated and
>scored all 30^12 (5.3x10^17) positions?


No, because of alpha/beta.  Many positions can be partially searched to prove
they are worse than the best found so far.  30^6 is a closer estimate, but that
ignores q-search and search extensions which drive that up.



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