Matrix (version 1.2-8)

sparseMatrix-class: Virtual Class "sparseMatrix" --- Mother of Sparse Matrices

Description

Virtual Mother Class of All Sparse Matrices

Slots

Extends

Class "Matrix", directly.

Methods

See also colSums, norm, ... for methods with separate help pages.

See Also

sparseMatrix, and its references, such as xtabs(*, sparse=TRUE), or sparse.model.matrix(), for constructing sparse matrices.

T2graph for conversion of "graph" objects (package graph) to and from sparse matrices.

Examples

showClass("sparseMatrix") ## and look at the help() of its subclasses
M <- Matrix(0, 10000, 100)
M[1,1] <- M[2,3] <- 3.14
M  ## show(.) method suppresses printing of the majority of rows

data(CAex); dim(CAex) # 72 x 72 matrix
determinant(CAex) # works via sparse lu(.)

## factor -> t( <sparse design matrix> ) :
(fact <- gl(5, 3, 30, labels = LETTERS[1:5]))
(Xt <- as(fact, "sparseMatrix"))  # indicator rows

## missing values --> all-0 columns:
f.mis <- fact
i.mis <- c(3:5, 17)
is.na(f.mis) <- i.mis
Xt != (X. <- as(f.mis, "sparseMatrix")) # differ only in columns 3:5,17
stopifnot(all(X.[,i.mis] == 0), all(Xt[,-i.mis] == X.[,-i.mis]))