spam (version 0.13-2)

spam: Sparse Matrix Class

Description

This group of functions evaluates and coerces changes in class structure.

Usage

spam(x, nrow = 1, ncol = 1, eps = .Spam$eps)
as.spam(x, eps = .Spam$eps)
is.spam(x)

Arguments

x

is a matrix, or vector object, of either dense or sparse form

nrow

number of rows of matrix

ncol

number of columns of matrix

eps

A tolerance parameter: elements of x such that abs(x) < eps set to zero. This argument is only relevant when coercing matrices from dense to sparse form. Defaults to eps = .Spam$eps

Details

The function as.spam acts like matrix to coerce a vector object to a sparse matrix object of class spam.

See Also

SPAM general overview of the package.

Examples

# old message, do not loop, when you create a large sparse matrix
set.seed(13)
nz <- 128
ln <- nz^2
smat <- spam(0,ln,ln)
is <- sample(ln,nz) 
js <- sample(ln,nz) 
system.time(for (i in 1:nz) smat[is[i], js[i]] <- i)
system.time(smat[cbind(is,js)] <- 1:nz)

getClass("spam")