spam {spam} | R Documentation |
This group of functions evaluates and coerces changes in class structure.
spam(x, nrow = 1, ncol = 1, eps = .Spam$eps) as.spam(x, eps = .Spam$eps) is.spam(x)
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 |
The function as.spam
acts like matrix
to coerce a vector object to
a sparse matrix object of class spam
.
SPAM
general overview of the package.
# 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")