nonzero function from DAPAR package (https://github.com/edyp-lab/DAPAR) temporarily including a local version to avoid installation issues

nonzero function from DAPAR package (https://github.com/edyp-lab/DAPAR) temporarily including a local version to avoid installation issues

Usage

nonzero(x)

Arguments

x

A sparse matrix of class "dgCMatrix".

Value

A two-column matrix containing the indices of the non-zero elements in the input matrix.