gmult {gellipsoid}

Linear Transformation of a Generalized Ellipsoid

Description

Linear transformation of a generalized ellipsoid, including projections to subspaces.

Usage

gmult(A, G, epsfac = 2)

Arguments

A

A matrix describing a linear transformation, conforming to the U component of G for matrix multiplication.

G

A gell object

epsfac

Factor of .Machine$double.eps used to distinguish zero vs. positive singular values

Details

The matrix A can be non-singular, for a standard linear transformation, or singular, for a projection to a subspace.

Value

gell object

Note

This implementation should be changed so that it provides an S3 method for class "gell" objects for which it was intended.

Author(s)

Georges Monette

See Also

gell, dual, signature

Examples

(zplane <- gell(span = diag(3)[,1:2]))  # a plane

dual(zplane)  # orthogonal line
(zplane2 <- gmult( cbind( c(1,1,1), c(1,-1,0), c(1,0,-1)), zplane))

# correctly wipes out one dimension
(zplane3 <- gmult( cbind( c(1,0,0), c(1,0,0), c(0,0,1)), zplane))