refund (version 0.1-23)

cmdscale_lanczos: Faster multi-dimensional scaling

Description

This is a modified version of cmdscale that uses the Lanczos procedure (slanczos) instead of eigen. Called by smooth.construct.pco.smooth.spec.

Usage

cmdscale_lanczos(d, k = 2, eig = FALSE, add = FALSE, x.ret = FALSE)

Arguments

d

a distance structure as returned by dist, or a full symmetric matrix of distances or dissimilarities.

k

the maximum dimension of the space which the data are to be represented in; must be in {1, 2, ..., n-1}.

eig

logical indicating whether eigenvalues should be returned.

add

logical indicating if the additive constant of Cailliez (1983) should be computed, and added to the non-diagonal dissimilarities such that the modified dissimilarities are Euclidean.

x.ret

indicates whether the doubly centred symmetric distance matrix should be returned.

Value

as cmdscale

References

Cailliez, F. (1983). The analytical solution of the additive constant problem. Psychometrika, 48, 343-349.

See Also

smooth.construct.pco.smooth.spec