Methods for coercion from and to sparse matrices from package SparseM
are provided here, for ease of porting functionality to the
Matrix package, and comparing functionality of the two
packages. All these work via the usual `as(., "<class>")`

coercion,

as(from, Class)

- from = "matrix.csr", to = "dgRMatrix"
...

- from = "matrix.csc", to = "dgCMatrix"
...

- from = "matrix.coo", to = "dgTMatrix"
...

- from = "dgRMatrix", to = "matrix.csr"
...

- from = "dgCMatrix", to = "matrix.csc"
...

- from = "dgTMatrix", to = "matrix.coo"
...

- from = "sparseMatrix", to = "matrix.csr"
...

- from = "matrix.csr", to = "dgCMatrix"
...

- from = "matrix.coo", to = "dgCMatrix"
...

- from = "matrix.csr", to = "Matrix"
...

- from = "matrix.csc", to = "Matrix"
...

- from = "matrix.coo", to = "Matrix"
...

The documentation in CRAN package SparseM, such as
`SparseM.ontology`

, and one important class,
`matrix.csr`

.