discrcoord {fpc} | R Documentation |
Discriminant coordinates/canonical variates
Description
Computes discriminant coordinates, sometimes referred to as "canonical variates" as described in Seber (1984).
Usage
discrcoord(xd, clvecd, pool = "n", ...)
Arguments
xd |
the data matrix; a numerical object which can be coerced to a matrix. |
clvecd |
integer vector of class numbers; length must equal
|
pool |
string. Determines how the within classes covariance is pooled. "n" means that the class covariances are weighted corresponding to the number of points in each class (default). "equal" means that all classes get equal weight. |
... |
no effect |
Details
The matrix T (see Seber (1984), p. 270) is inverted by use of
tdecomp
, which can be expected to give
reasonable results for singular within-class covariance matrices.
Value
List with the following components
ev |
eigenvalues in descending order. |
units |
columns are coordinates of projection basis vectors.
New points |
proj |
projections of |
Author(s)
Christian Hennig christian.hennig@unibo.it https://www.unibo.it/sitoweb/christian.hennig/en/
References
Seber, G. A. F. (1984). Multivariate Observations. New York: Wiley.
See Also
plotcluster
for straight forward discriminant plots.
batcoord
for discriminating projections for two classes,
so that also the differences in variance are shown (discrcoord
is
based only on differences in mean).
rFace
for generation of the example data used below.
Examples
set.seed(4634)
face <- rFace(600,dMoNo=2,dNoEy=0)
grface <- as.integer(attr(face,"grouping"))
dcf <- discrcoord(face,grface)
plot(dcf$proj,col=grface)
# ...done in one step by function plotcluster.