### Simple fallback methods for all dense matrices
### These are "cheap" to program, but potentially far from efficient;
### Methods for specific subclasses will overwrite these:

## dense to sparse: as() will take the ``closest'' match
setAs("denseMatrix", "dsparseMatrix",
      function(from) as(as(from, "dgeMatrix"), "dsparseMatrix"))

## setAs("denseMatrix", "dgCMatrix",
##       function(from) as(as(from, "dgeMatrix"), "dgCMatrix"))
## setAs("denseMatrix", "dgTMatrix",
##       function(from) as(as(from, "dgeMatrix"), "dgTMatrix"))


setMethod("show", signature(object = "denseMatrix"),
          function(object) prMatrix(object))
##- ## FIXME: The following is only for the "dMatrix" objects that are not
##- ##	      "dense" nor "sparse" -- i.e. "packed" ones :
##- ## But these could be printed better -- "." for structural zeros.
##- setMethod("show", signature(object = "dMatrix"), prMatrix)
##- ## and improve this as well:
##- setMethod("show", signature(object = "pMatrix"), prMatrix)
##- ## this should now be superfluous [keep for safety for the moment]:


## Using "index" for indices should allow
## integer (numeric), logical, or character (names!) indices :

setMethod("[", signature(x = "denseMatrix", i = "index", j = "missing",
			 drop = "logical"),
          function (x, i, drop) {
              r <- as(x, "matrix")[i, , drop=drop]
              if(is.null(dim(r))) r else as(r, class(x))
          })

setMethod("[", signature(x = "denseMatrix", i = "missing", j = "index",
			 drop = "logical"),
          function (x, j, drop) {
              r <- as(x, "matrix")[, j, drop=drop]
              if(is.null(dim(r))) r else as(r, class(x))
          })

setMethod("[", signature(x = "denseMatrix", i = "index", j = "index",
			 drop = "logical"),
          function (x, i, j, drop) {
              r <- callGeneric(x = as(x, "matrix"), i=i, j=j, drop=drop)
              if(is.null(dim(r))) r else as(r, class(x))
          })

## Now the "[<-" ones --- see also those in ./Matrix.R
## It's recommended to use setReplaceMethod() rather than setMethod("[<-",.)
## even though the former is currently just a wrapper for the latter

## FIXME: 1) These are far from efficient
## -----  2) value = "numeric" is only ok for "ddense*"
##        3) as(<matrix>, class(x)) can be very wrong for symmetric, triangular..
setReplaceMethod("[", signature(x = "denseMatrix", i = "index", j = "missing",
                                value = "numeric"),
                 function (x, i, value) {
                     r <- as(x, "matrix")
                     r[i, ] <- value
                     as(r, class(x))
                 })

setReplaceMethod("[", signature(x = "denseMatrix", i = "missing", j = "index",
                                value = "numeric"),
                 function (x, j, value) {
                     r <- as(x, "matrix")
                     r[, j] <- value
                     as(r, class(x))
                 })

setReplaceMethod("[", signature(x = "denseMatrix", i = "index", j = "index",
                                value = "numeric"),
                 function (x, i, j, value) {
                     r <- as(x, "matrix")
                     r[i, j] <- value
                     as(r, class(x))
                 })


## not exported:
setMethod("isSymmetric", signature(object = "denseMatrix", tol = "ANY"),
	  function(object, tol = 100*.Machine$double.eps) {
	      ## pretest: is it square?
	      d <- dim(object)
	      if(d[1] != d[2]) return(FALSE)
	      ## else slower test
	      if (is(object,"dMatrix"))
		  isTRUE(all.equal(as(object, "dgeMatrix"),
				   as(t(object), "dgeMatrix"), tol = tol))
	      else if (is(object, "lMatrix"))# not possible currently
		  ## test for exact equality; FIXME(?): identical() too strict?
		  identical(as(object, "lgeMatrix"),
			    as(t(object), "lgeMatrix"))
	      else stop("not yet implemented")
	  })