You can sort the eigenvalues in the order you want with
o <- order(Re(e$values), decreasing = TRUE)
or
o <- order(abs(Re(e$values)), decreasing = TRUE)
followed by
e$values[o]
where 'e' is the object that eigen returns.
The main argument to order() is what you want to sort by and the subscript
expression e$values[o] does the rearranging. You can subscript e$vectors
to rearrange them as well.
Bill Dunlap
TIBCO Software
wdunlap tibco.com
On Tue, May 5, 2015 at 10:49 AM, Luis Borda de Agua <lba...@gmail.com>
wrote:
> I’m using R 3.1.3 in OS X 10.10.3 (Yosemite)
>
> I use the function “eigen” to calculate the eigenvalues of matrix where
> each element is sampled from a given distribution (normal, beta, etc.).
> According to the information provided:
> "values
> a vector containing the p eigenvalues of x, sorted in decreasing order,
> according to Mod(values)"
>
>
> However, for my purposes it would be important to “fix” the order by which
> the eigenvalues are presented. To be more specific, I would like to know
> each time I calculated the eigenvalues from a set of sampled matrix
> elements which is the eigenvalue that provides the largest (or the
> smallest) real part.
>
> Is there an easy way to enforce this? (I could not find an option in
> "eigen".)
>
> Is there another function in R that calculates the eigenvalues and shows
> their values without sorting them?
>
> Thank you in advance,
>
> Luís Borda de Água
>
>
> [[alternative HTML version deleted]]
>
> ______________________________________________
> R-help@r-project.org mailing list -- To UNSUBSCRIBE and more, see
> 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.
[[alternative HTML version deleted]]
______________________________________________
R-help@r-project.org mailing list -- To UNSUBSCRIBE and more, see
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.
