nonzero-methods {Ringo} | R Documentation |
Auxiliary functions to retrieve the indices of non-zero elements in sparse matrices.
A two-column matrix. Each row gives the row and column index of a
non-zero element in the supplied matrix x
.
dgCMatrix
matrix.csr
matrix
; equivalent to
which(x != 0, arr.ind=TRUE)
Originally we used the matrix.csr
class from SparseM, but we
have switched to the class dgCMatrix
from package Matrix, as
that package is part of the R distribution bundle now.
The idea is to have a function similar to
which(x != 0, arr.ind=TRUE)
if x
is a matrix.
(A <- matrix(c(0,0,0,0,0,1,0,0,0,0,0,0,0,0,-34), nrow=5, byrow=TRUE)) str(A.dgc <- as(A, "dgCMatrix")) nonzero(A.dgc) A2.dgc <- Matrix::cBind(A.dgc, A.dgc) as.matrix(A2.dgc) nonzero(A2.dgc)