#### Superclass Methods for all sparse nonzero-pattern matrices

setAs("CsparseMatrix", "nsparseMatrix",
      function(from) .Call(Csparse_to_nz_pattern, from,
			   is(from, "triangularMatrix")))


###------- Work via  as(*, lgC) : ------------

## For multiplication operations, sparseMatrix overrides other method
## selections.  Coerce a ddensematrix argument to a lsparseMatrix.

setMethod("%*%", signature(x = "nsparseMatrix", y = "ndenseMatrix"),
          function(x, y) callGeneric(x, as(y, "nsparseMatrix")))

setMethod("%*%", signature(x = "ndenseMatrix", y = "nsparseMatrix"),
          function(x, y) callGeneric(as(x, "nsparseMatrix"), y))

setMethod("crossprod", signature(x = "nsparseMatrix", y = "ndenseMatrix"),
          function(x, y = NULL) callGeneric(x, as(y, "nsparseMatrix")))

setMethod("crossprod", signature(x = "ndenseMatrix", y = "nsparseMatrix"),
          function(x, y = NULL) callGeneric(as(x, "nsparseMatrix"), y))

## and coerce lsparse* to lgC*
setMethod("%*%", signature(x = "nsparseMatrix", y = "nsparseMatrix"),
          function(x, y) callGeneric(as(x, "ngCMatrix"), as(y, "ngCMatrix")))

setMethod("crossprod", signature(x = "nsparseMatrix", y = "nsparseMatrix"),
          function(x, y = NULL)
          callGeneric(as(x, "ngCMatrix"), as(y, "ngCMatrix")))

setMethod("!", "nsparseMatrix",
          ## turns FALSE to TRUE --> dense matrix
          function(e1) !as(e1, "ngeMatrix"))

setMethod("diag", signature(x = "nsparseMatrix"),
	  function(x, nrow, ncol = n) diag(as(x, "ngCMatrix")))