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Subject: Re: Is my move ordering acceptable?

Author: Uri Blass

Date: 09:32:47 10/30/03

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On October 30, 2003 at 12:27:16, Tord Romstad wrote:

>On October 30, 2003 at 11:05:41, Uri Blass wrote:
>
>>On October 30, 2003 at 10:46:09, Vladimir Medvedev wrote:
>>
>>>>>In order to find out how good my move ordering is, I determined to check
>>>>>which percentage of the cutoffs occured on the first move searched.
>>>
>>>Is branching factor more or less accurate parameter to evaluate quality of
>>>sorting moves?
>
>Perhaps, but how do you measure the branching factor?  I have asked this
>question here before, but never recieved any answer.
>
>>You can improve your branching factor by pruning or reduce it by extensions.
>
>Everybody always seem to claim that extensions increase the branching factor
>(I suppose that is what you meant, although you wrote "reduce")

You are right.

, but it is
>not at all obvious to me why this should be so.  On the few occasions I have
>experimented with this myself, removing all extensions has not resulted in
>a noticably better branching factor.  Of course the program needs fewer
>nodes to complete a given search depth without extensions, but the difference
>does not seem to be exponential.  Perhaps more detailed and careful
>experiments would have given a different result.
>
>Tord

I think that it is dependent on your extension and I do not claim that every
extension and every pruning change the branching factor.

Uri



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