[R] Total inertia in package Vegan?

[Gavin Simpson]

On Wed, 2010-11-17 at 13:23 +0100, Hedberg Peter wrote:
> Dear all at the R-project help list.
> 
> I have run into a problem when it comes to getting values for "total
> inertia" and "R-squared" for my DCA using "decorana" in the package
> "vegan". I have tried the "goodness" function, but the reply indicates
> that it does not work with "decorana" class objects. In Canoco one
> gets the Total inertia in the output together with 4 eigenvalues. In
> decorana one gets the 4 eigenvalues, but not the Total inertia.
> 
> Is there a way for me to get the Total inertia without having to go
> over to Canoco?

OK, I might well be being incredibly stupid, but Total Inertia doesn't
change with CA/DCA. Just run cca() on your matrix and grab the inertia.
Whether you can compare the eigenvalues from decorana() and cca() I
can't quite remember. Jari should be able to tell you - drop us a line
on the Vegan R-Forge page:

https://r-forge.r-project.org/forum/forum.php?forum_id=194&group_id=68

I'll take this opportunity to question why you are using DCA at all?

G

> Best regards,
> 
> Petter Hedberg
> 
> 
> ___________________________________
> NOCC, http://nocc.sourceforge.net
> 
> 
> 
> 

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