<x-charset ISO-8859-1>Hi to ADE users,
I wonder whether the question of Bruno Rossaro was answered.
Anyway, concerning the operation for getting a trait-by-sites matrix
(proportion of q column-modalities of r traits in n row-sites) from a
traits-by-species matrix (proportion of q column-modalities of r traits of t
row-species) and a sites-by-species matrix (Abundance of t row-species in n
column-sites) at least two possibilities are available in ADE-4.
The first one is to use the the FuzFCMean option of the Fuzzyvar module.
This requires first to process the trait-by-species matrix using the Read
Fuzzy File option of the same module and to perform a correspondence
analysis on the sites-by-species matrix (file .fcta required by the
FuzFCMean option). Note than if you make the co-inertia analysis between the
traits-by-species matrix and the sites-by-species matrix matrix, you have a
way for testing the significance of the trait-by-sites matrix (see Doc
module of ADE-4).
If you do not want to perform a correspondence analysis on the
sites-by-species matrix, you may compute the product of the two matrices
more straight. This just requires that you process the trait-by-species
matrix using the Read Fuzzy File option of the Fuzzyvar module and you
transform the sites-by-species matrix into frequencies (by column option).
You can then multiply the two matrices using the Diagonal Inner Product of
the MatAlg module (with Inner product D = 1,1,...,1).
The traits-by-species matrix can then be processed by Fuzzy FCA, Fuzzy PCA
or else (after being processed by the reading option).
All the very best,
Sylvain Dolédec
----------------------------------------
UCB Lyon 1
CNRS - Ecologie des Hydrosystèmes Fluviaux
Bât 401C
43 Bd du 11 novembre 1918
69622 Villeurbanne
phone: +33 (0) 472431363
fax: +33 (0) 472431141
----------------------------------------
http://ecolstat.univ-lyon1.fr/equipe/accueil/
http://pbil.univ-lyon1.fr/ADE-4/ADE-4.html
----------
>De : Rossaro Bruno <rossaro@mailserver.unimi.it>
>À : adelist@biomserv.univ-lyon1.fr
>Objet : fuzzy corresp analysis
>Date : Mar 23 mai 2000 16:12
>
> Dear collegues,
> I have read with interest the papers published in Freshwat. Biol.
> using fuzzy correspondence analysis.
> charvet@lyon.cemagref.fr
> In particular:
> Authors
> Charvet S. Statzner B. Usseglio-Polatera P. Dumont B.
> Author e-mail Address
> charvet@lyon.cemagref.fr
> Title
> Traits of benthic macroinvertebrates in semi-natural French streams: an
> initial application to biomonitoring in Europe
> Source
> Freshwater Biology. 43(2):277-296, 2000 Feb.
> In this paper I have not well understood how fuzzy correspondence analysis
> was carried out on a trait category matrix
> weighted on species abundances.
> Suppose you have a trait matrix with t species and m modalities (tMm) and
> an abundance matrix with n sites and t species
> (nYt). It seems that something such as a product matrix nYtMm was
> performed, and fuzzy correspoindence analysis was carried out on this matrix.
> Can somebody help me ?
> Sincerely yours
> Bruno Rossaro
> _______________________________________
> prof. Bruno Rossaro
> Department of Biology Section Ecology
> Univ. of Milano
> via Celoria 26 I 20133 Milano (office)
> v.le Murillo 21 I 20149 Milano (private address)
> tel 039_2_2_26604_371
> fax 0039_2_26604_361
> e-mail: Bruno.Rossaro@unimi.it
> http://www.sezionecologia.unimi.it
>
</x-charset>
This archive was generated by hypermail 2b30 : Mon Feb 12 2001 - 09:24:55 MET