eigenvals {vegan}R Documentation

Extract Eigenvalues from an Ordination Object

Description

Function extracts eigenvalues from an object that has them. Many multivariate methods return such objects.

Usage

eigenvals(x, ...)
## S3 method for class 'cca':
eigenvals(x, constrained = FALSE, ...)
## S3 method for class 'eigenvals':
summary(object, ...)

Arguments

x An object from which to extract eigenvalues.
object An eigenvals result object.
constrained Return only constrained eigenvalues.
... Other arguments to the functions (usually ignored)

Details

This is a generic function that has methods for cca, wcmdscale, prcomp and princomp result objects. The default method also extracts eigenvalues if the result looks like being from eigen or svd. Functions prcomp and princomp contain square roots of eigenvalues that all called standard deviations, but eigenvals function returns their squares. Function svd contains singular values, but function eigenvals returns their squares. For constrained ordination methods cca, rda and capscale the function returns the both constrained and unconstrained eigenvalues concatenated in one vector, but the partial component will be ignored. However, with argument constrained = TRUE only constrained eigenvalues are returned.

The summary of eigenvals result returns eigenvalues, proportion explained and cumulative proportion explained.

Value

An object of class "eigenvals" which is a vector of eigenvalues.

Author(s)

Jari Oksanen.

See Also

eigen, svd, prcomp, princomp, cca, rda, capscale, wcmdscale, cca.object.

Examples

data(varespec)
data(varechem)
mod <- cca(varespec ~ Al + P + K, varechem)
ev <- eigenvals(mod)
ev
summary(ev)

[Package vegan version 1.16-32 Index]