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