#### Sparse Matrices in Compressed column-oriented format

### contains = "dsparseMatrix"

setAs("dgCMatrix", "dgTMatrix",
      function(from) .Call("compressed_to_dgTMatrix", from, TRUE))

setAs("dgCMatrix", "matrix",
      function(from) .Call("csc_to_matrix", from))

setAs("dgCMatrix", "dgeMatrix",
      function(from) .Call("csc_to_dgeMatrix", from))

setAs("dgCMatrix", "dgBCMatrix",
      function(from) new("dgBCMatrix", p = from@p, i = from@i,
                         x = array(from@x, c(1, 1, length(from@x)))))

setAs("dgCMatrix", "lgCMatrix",
      function(from) new("lgCMatrix", i = from@i, p = from@p,
                         Dim = from@Dim, Dimnames = from@Dimnames))

setAs("matrix", "dgCMatrix",
      function(from) {
          storage.mode(from) <- "double"
          .Call("matrix_to_csc", from)
      })

setAs("dgeMatrix", "dgCMatrix", # dgeM* is "double":
      function(from) .Call("matrix_to_csc", as(from, "matrix")))


setMethod("crossprod", signature(x = "dgCMatrix", y = "missing"),
          function(x, y = NULL) .Call("csc_crossprod", x),
          valueClass = "dsCMatrix")

setMethod("crossprod", signature(x = "dgCMatrix", y = "dgeMatrix"),
          function(x, y = NULL) .Call("csc_matrix_crossprod", x, y, TRUE),
          valueClass = "dgeMatrix")

setMethod("crossprod", signature(x = "dgCMatrix", y = "matrix"),
          function(x, y = NULL) .Call("csc_matrix_crossprod", x, y, FALSE),
          valueClass = "dgeMatrix")

##setMethod("crossprod", signature(x = "dgCMatrix", y = "numeric"),
##          function(x, y = NULL) callGeneric(x, as.matrix(y)),
##          valueClass = "dgeMatrix")

## setMethod("crossprod", signature(x = "dgCMatrix", y = "numeric"),
##           function(x, y = NULL) .Call("csc_matrix_crossprod", x, as.matrix(y)))

setMethod("tcrossprod", signature(x = "dgCMatrix"),
          function(x) .Call("csc_tcrossprod", x))

setMethod("diag", signature(x = "dgCMatrix"),
          function(x = 1, nrow, ncol = n) .Call("csc_getDiag", x))

## try to define for "Matrix" -- once and for all -- but that fails -- why?
setMethod("dim", signature(x = "dgCMatrix"),
          function(x) x@Dim, valueClass = "integer")

setMethod("t", signature(x = "dgCMatrix"),
          function(x) .Call("csc_transpose", x),
          valueClass = "dgCMatrix")

setMethod("image", "dgCMatrix",
          function(x, ...) {
              x <- as(x, "dgTMatrix")
              callGeneric()
          })

setMethod("%*%", signature(x = "dgCMatrix", y = "dgeMatrix"),
          function(x, y) .Call("csc_matrix_mm", x, y, TRUE, FALSE),
          valueClass = "dgeMatrix")

setMethod("%*%", signature(x = "dgCMatrix", y = "matrix"),
          function(x, y) .Call("csc_matrix_mm", x, y, FALSE, FALSE),
          valueClass = "dgeMatrix")

setMethod("%*%", signature(x = "dgeMatrix", y = "dgCMatrix"),
          function(x, y) .Call("csc_matrix_mm", y, x, TRUE, TRUE),
          valueClass = "dgeMatrix")

setMethod("%*%", signature(x = "matrix", y = "dgCMatrix"),
          function(x, y) .Call("csc_matrix_mm", y, x, FALSE, TRUE),
          valueClass = "dgeMatrix")