Matrix (version 0.999375-42)

LU-class: LU (dense) Matrix Decompositions

Description

The "LU" class is the virtual class of LU decompositions of real matrices. "denseLU" the class of LU decompositions of dense real matrices.

Objects from the Class

Objects can be created by calls of the form new("denseLU", ...). More commonly the objects are created explicitly from calls of the form lu(mm) where mm is an object that inherits from the "dgeMatrix" class or as a side-effect of other functions applied to "dgeMatrix" objects.

Extends

"LU" directly extends the virtual class "MatrixFactorization".

"denseLU" directly extends "LU".

See Also

class sparseLU for LU decompositions of sparse matrices; further, class dgeMatrix and functions lu, expand.

Examples

set.seed(1)
mm <- Matrix(round(rnorm(9),2), nrow = 3)
mm
str(lum <- lu(mm))
elu <- expand(lum)
elu # three components: "L", "U", and "P", the permutation
elu$L %*% elu$U
(m2 <- with(elu, P %*% L %*% U)) # the same as 'mm'
stopifnot(all.equal(as(mm, "matrix"),
                    as(m2, "matrix")))