[R-sig-eco] envfit calculation

[Gavin Simpson]

On Mon, 2011-12-05 at 09:39 -0800, dan clune wrote:
> Hello R-Ecologists,
> I'm looking for clarification on how vectors in function envfit are
> calculated. I understand how to use the function, it is pretty
> straightforward. But after reading the documentation I am still
> wondering exactly how the vectors are calculated internally by the
> function. 

It is covered in Jongman, ter Braak & van Tongeren (1995) Data Analysis
in Community and Landscape Ecology. Cambridge University Press. It is in
the ordination chapter. I'm away from my copy at the moment so can't
point you to it directly I'm afraid.

However, that might not help you understand the R code as IIRC Jari has
some pretty efficient code to do fitting. If that was your aim, it might
help to speak to Jari on the vegan help or discussion lists on
r-forge.r-project.org.

I've been meaning to write a blog post about envfit for a wee while, but
that would only be from the point of view of what the method/idea is
doing, not from understanding the codes Jari used to implement it.

HTH

G

> Can anyone point me toward a more detailed explanation of the calculations?
> Thanks for any help,
> Dan
> 
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> 
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