Dear Steve,
If the direction is important, you can use that information as a
separate matrix with signs to scale up its effect. Because distance
can't be negative, you might end up with numbers hard to interpret.
Yours,
Peter
Péter Sólymos
Alberta Biodiversity Monitoring Institute
Department of
On Thu, Oct 1, 2009 at 1:46 PM, Jari Oksanen wrote:
>
>
> Sarah & Steve,
>
> This was the design I had on my mind. However, I was not sure how
> skew-symmetry actually was defined, and therefore I didn't know if free
> permutation of rows and columns (even when done correctly like above) will
> re
On 1/10/09 20:36 PM, "Sarah Goslee" wrote:
> I can only speak for the mantel() within ecodist, but I can tell you that it
> will not take full matrices - the upper triangle will be dropped. You could
> roll your own very easily, but it would be exceedingly slow, eg:
>
> mat1 <- # some square
I can only speak for the mantel() within ecodist, but I can tell you that it
will not take full matrices - the upper triangle will be dropped. You could
roll your own very easily, but it would be exceedingly slow, eg:
mat1 <- # some square skew-symmetric matrix
mat2 <- # some other square skew-sym
Steve,
My answer concerning the vegan part is so short that I top-post (my
apologies for those who are sensitive about this): No, you cannot use
non-symmetric matrices in mantel() functions in vegan. The functions use the
standard R distance objects which are regarded as symmetric. If you supply a
Hello All,
I'm interested in using the mantel()and mantel.partial() functions in the
'vegan' R package to examine fish morphology in several lakes with respect to
distance between lakes, lake elevation (above sea level) and various habitat
measures. For example, several authors have postulated
