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Subject: Re: Efficiency of moveordering()

Author: Vincent Diepeveen

Date: 06:34:23 09/09/00

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On September 09, 2000 at 02:02:46, TEERAPONG TOVIRAT wrote:

>Hi,
>
>I want to estimate the efficacy of each method
>of moveordering() . Some problems arise.

What you need to measure is the chance that the first move
selected is the best move in a position.

>Should I use branching factor to determine the
>efficacy ?  If so,the next problem is how to obtain

branching factor is heavily influenced by nullmove,
hashtable efficiency, accuracy of score returned by
hashtable etcetera.

To give example:
  Diep usually needs hell of alot of nodes a ply as any other program
  i know, taking into account that i only use nullmove.
  Yet the chance that the first move cutoffs in DIEP in a cutnode is
  a lot smaller as most other programs (about 0.85 in diep, versus
  about 0.90 for crafty). The node efficienty is however to a large
  extend there because of a small fliprate (chance that a node stored in
  hash as <= alpha gives a cutoff now).

  This is less 1% in DIEP namely.

Obviously the time needed a ply is even more influenced by other
factors as move ordering only.

>the factor ? It varies from ply to ply and from
>game to game. In order to approximate it, should
>I use geometric mean or arithmetic mean ?
>
>Or it would be better to use total searching time ?
>How u did it ?

>Thanks,
>Teerapong



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