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Brillouin index

Philipp Fischer
Dear colleagues.

I wonder if anybody knows about a procedure in R to calculate the Brillouin Diversity index.

I searched the net but did not find anything about it.

Thanks a lot for any help

Best, Philipp
***************************************************
Prof. Dr. Philipp Fischer
Head of AWI Center for Scientific Diving & Dept. In situ Ecology
Section Shelf Sea Systems
Alfred-Wegener-Institut
Biologische Anstalt Helgoland
Building A
D-27498 Helgoland
 
Phone: +49(4725)819-3344
Skype: fischer_philipp
Fax: +49(4725)819-3369
 
http://www.awi.de/People/show?pfischer
http://www.awi.de/en/infrastructure/underwater/scientific_diving/
http://www.awi.de/en/research/research_divisions/biosciences/shelf_sea_ecology/
http://www.forschungstauchen-deutschland.de




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Re: Brillouin index

MacQueen, Don
It's a pretty simple formula, according to the sources I found.

Here's a function that looks right to me, but I have no independent
calculation with which to check it.
(no guarantees!)

Hb <- function(ns) {
  N <- sum(ns)
  (lfactorial(N) - sum(lfactorial(ns)))/N
}

> ns <- c(3,5,2,8)
> Hb(ns)
[1] 1.028802




--
Don MacQueen

Lawrence Livermore National Laboratory
7000 East Ave., L-627
Livermore, CA 94550
925-423-1062





On 1/13/12 8:12 AM, "Philipp Fischer" <[hidden email]> wrote:

>Dear colleagues.
>
>I wonder if anybody knows about a procedure in R to calculate the
>Brillouin Diversity index.
>
>I searched the net but did not find anything about it.
>
>Thanks a lot for any help
>
>Best, Philipp
>***************************************************
>Prof. Dr. Philipp Fischer
>Head of AWI Center for Scientific Diving & Dept. In situ Ecology
>Section Shelf Sea Systems
>Alfred-Wegener-Institut
>Biologische Anstalt Helgoland
>Building A
>D-27498 Helgoland
>
>Phone: +49(4725)819-3344
>Skype: fischer_philipp
>Fax: +49(4725)819-3369
>
>http://www.awi.de/People/show?pfischer
>http://www.awi.de/en/infrastructure/underwater/scientific_diving/
>http://www.awi.de/en/research/research_divisions/biosciences/shelf_sea_eco
>logy/
>http://www.forschungstauchen-deutschland.de
>
>
>
>
>______________________________________________
>[hidden email] mailing list
>https://stat.ethz.ch/mailman/listinfo/r-help
>PLEASE do read the posting guide
>http://www.R-project.org/posting-guide.html
>and provide commented, minimal, self-contained, reproducible code.

______________________________________________
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https://stat.ethz.ch/mailman/listinfo/r-help
PLEASE do read the posting guide http://www.R-project.org/posting-guide.html
and provide commented, minimal, self-contained, reproducible code.
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Re: Brillouin index

bbolker
MacQueen, Don <macqueen1 <at> llnl.gov> writes:

>
> It's a pretty simple formula, according to the sources I found.
>
> Here's a function that looks right to me, but I have no independent
> calculation with which to check it.
> (no guarantees!)
>
> Hb <- function(ns) {
>   N <- sum(ns)
>   (lfactorial(N) - sum(lfactorial(ns)))/N
> }
>
> > ns <- c(3,5,2,8)
> > Hb(ns)
> [1] 1.028802

  Another source I found said that the index should be scaled
by its maximum value, which assumes that all species are of
equal diversity, which would be

  (lfactorial(N)-sum(lfactorial(mean(ns)))/N

(the fact that mean(ns) is non-integer is not a problem; lfactorial()
accepts non-integral values).

  Future questions like this *might* get more traction on
the [hidden email] list ...

______________________________________________
[hidden email] mailing list
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and provide commented, minimal, self-contained, reproducible code.
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