Convert sparse matrix pointers to indices and vice versa

Convert sparse matrix pointers to indices and vice versa

Usage

IndexToPointer(j)

PointerToIndex(p)

Source

PointerToIndex came from StackOverflow

Arguments

j

A vector of sparse matrix colum indices

p

A vector of sparse matrix pointers

Value

IndexToPointer: A vector of index pointers (p)

PointerToIndex: A vector of column (j) indices

Author

PointerToIndex was written by Josh O'Brien on StackOverflow

Examples

# \donttest{
dat <- dat <- c(0, 0, 1, 4, 0, 2, 0, 9, 0)
smat <- Matrix::Matrix(data = dat, nrow = 3, sparse = TRUE)
j <- srtdisk:::PointerToIndex(p = smat@p)
Matrix::sparseMatrix(i = smat@i + 1, j = j, x = smat@x)
#> 3 x 3 sparse Matrix of class "dgCMatrix"
#>           
#> [1,] . 4 .
#> [2,] . . 9
#> [3,] 1 2 .
p <- srtdisk:::IndexToPointer(j = j)
Matrix::sparseMatrix(i = smat@i + 1, p = p, x= smat@x)
#> 3 x 3 sparse Matrix of class "dgCMatrix"
#>           
#> [1,] . 4 .
#> [2,] . . 9
#> [3,] 1 2 .
# }