Retrieve the indices of non-zero elements in sparse matrices

This function retrieves the indices of non-zero elements in sparse matrices of class dgCMatrix from package Matrix. This function is largely inspired from the package RINGO.

Usage

nonzero(x)

Arguments

x

A sparse matrix of class dgCMatrix

Value

A two-column matrix

Author

Samuel Wieczorek

Examples

library(Matrix)
mat <- Matrix(c(0, 0, 0, 0, 0, 1, 0, 0, 1, 1, 0, 0, 0, 0, 1),
    nrow = 5, byrow = TRUE, sparse = TRUE)
res <- nonzero(mat)