nMatrix-class: Class "nMatrix" of Non-zero Pattern Matrices
In bedatadriven/renjin-matrix: Sparse and Dense Matrix Classes and Methods

Description Slots Methods See Also Examples

The nMatrix class is the virtual “mother” class of all non-zero pattern (or simply pattern) matrices in the Matrix package.

Common to all matrix object in the package:

Dim:: Object of class "integer" - the dimensions of the matrix - must be an integer vector with exactly two non-negative values.
Dimnames:: list of length two; each component containing NULL or a character vector length equal the corresponding Dim element.

There is a bunch of coercion methods (for as(..)), e.g.,

coerce: signature(from = "matrix", to = "nMatrix"): Note that these coercions (must) coerce NAs to non-zero, hence conceptually TRUE. This is particularly important when sparseMatrix objects are coerced to "nMatrix" and hence to nsparseMatrix.
coerce: signature(from = "dMatrix", to = "nMatrix"), and
coerce: signature(from = "lMatrix", to = "nMatrix"): For dense matrices with NAs, these coercions are valid since Matrix version 1.2.0 (still with a warning or a message if "Matrix.warn", or "Matrix.verbose" options are set.)
coerce: signature(from = "nMatrix", to = "matrix"): ...
coerce: signature(from = "nMatrix", to = "dMatrix"): ...
coerce: signature(from = "nMatrix", to = "lMatrix"): ...

— — —

Additional methods contain group methods, such as

Ops: signature(e1 = "nMatrix", e2 = "...."), ...
Arith: signature(e1 = "nMatrix", e2 = "...."), ...
Compare: signature(e1 = "nMatrix", e2 = "...."), ...
Logic: signature(e1 = "nMatrix", e2 = "...."), ...
Summary: signature(x = "nMatrix", "...."), ...

The classes lMatrix, nsparseMatrix, and the mother class, Matrix.

getClass("nMatrix")

L3 <- Matrix(upper.tri(diag(3)))
L3 # an "ltCMatrix"
as(L3, "nMatrix") # -> ntC*

## similar, not using Matrix()
as(upper.tri(diag(3)), "nMatrix")# currently "ngTMatrix"