Thankyou very much Jari!
I think that it is nearly ok
what I would like to have is the same as in
RsquareAdj(vegan::rda(yy,xx))
that is a GLOBAL measure of the association
BUT...I want it for a multiple-multivariate lm model that does not include the
intercept;
an alternative could be to build a rda design for the exclusion of intercept
but I really cannot figure out how to do it.
I think I just need to compute the average of single adjusted r squared from
the output of your line of code,
But the results are not identical
EXAMPLE WITH INTERCEPT IN ORDER TO COMPARE WITH RDA
RsquareAdj(vegan::rda(yy,xx))
mean(sapply(summary(lm(yy~xx)), function(x) c("r.squared" = x$r.squared,
"adj.r.squared" = x$adj.r.squared))[2,])
Or.... I just miss something in this computation
Thanks again for any further suggestion
________________________________________
Da: Jari Oksanen <jari.oksa...@oulu.fi>
Inviato: giovedì 3 ottobre 2013 14.25
A: Paolo Piras; r-sig-ecology@r-project.org
Oggetto: RE: [R-sig-eco] vegan RsquareAdj() for lm models
Specific reason is that nobody has implemented this. These things don't come by
automatic writing, but somebody must do them.
What would you expect to get? Is this what was on your mind:
> sapply(summary(lm(yy~xx-1)), function(x) c("r.squared" = x$r.squared,
> "adj.r.squared" = x$adj.r.squared))
Response Y1 Response Y2 Response Y3 Response Y4
r.squared 0.06845032 0.04788037 0.01702738 0.11253059
adj.r.squared -0.01255400 -0.03491264 -0.06844849 0.03535934
This could be implemented, but (1) is this what you or anybody else would like
to have?, (2) how many things would it break by returning several values
instead of one?
If you want to have this, you really do not need to use vegan.
vegan:::RsquareAdj.lm() takes its results from summary(<lm_object>). You can
use that stats:::summary.lm directly.
Cheers, Jari Oksanen
________________________________________
From: r-sig-ecology-boun...@r-project.org [r-sig-ecology-boun...@r-project.org]
on behalf of Paolo Piras [paolo.pi...@uniroma3.it]
Sent: 03 October 2013 14:59
To: r-sig-ecology@r-project.org
Subject: [R-sig-eco] vegan RsquareAdj() for lm models
Dear list,
I would like to easily compute the adjusted R-square in a lm model without
intercept (excluding the intercept is essential for my analysis)
I found that RsquareAdj() in vegan returns NA if the argument is a
multiple-multivariate lm model thus including multivariate responses and
multiple predictors, while it works for univariate response and multiple
predictors.
For example:
library(vegan)
yy<-matrix(rnorm(200,0,1),ncol=4)
xx<-matrix(rnorm(200,0,1),ncol=4)
RsquareAdj(lm(yy~xx-1))
RsquareAdj(lm(yy[,1]~xx-1))
There some specific reason for this behavior?
Thanks in advance for any advice
best regards
Poalo
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