Hi,
The Matrix package and the as.matrix method do not seem to be compatible inside
of a package.
Here's an example. I've created a simple package "mat" that defines an
eponymous class and as.matrix method on that class. All is well, unless that
package has the Matrix package in its Depends or Imports (and imports, e.g. the
"Diagonal" function). Then my as.matrix method stops working, even if I'm not
using any part of the Matrix package.
Here's an example on R 3.3.2:
First, create an empty package "mat" (e.g. with package.skeleton) with one file
in mat/R/mat.R with the following contents:
setClass("mat", representation(H="matrix"))
mat <- function(H) new("mat", H=H)
setMethod("as.matrix", signature("mat"), function(x, ...) crossprod(x@H))
testmat <- function() {
H <- matrix(1:3, 1, 3)
M <- mat(H)
as.matrix(M)
}
Then install the mat package :
> require(mat)
> testmat()
[,1] [,2] [,3]
[1,] 1 2 3
[2,] 2 4 6
[3,] 3 6 9
All works fine!
Now add "Depends: Matrix" into the package's DESCRIPTION file (alternatively
add "Imports: Matrix" and 'importFrom("Matrix","Diagonal")' in the NAMESPACE).
Try again:
> require(mat)
> testmat()
Error in as.vector(data) :
no method for coercing this S4 class to a vector
Bug? If not, can anyone provide a work around? In my case, I'd like to mix
matrix and Matrix functions in my package, but am obviously having difficulty.
I've come across a somewhat similar report on stackoverflow
http://stackoverflow.com/questions/13812373/overloading-operator-in-r-s4-classes-and-matrix-package
regarding defining the "+" operator with the Matrix package, but I don't think
the solution or the problem quite applies.
Thanks in advance, Robert
> R.version
_
platform x86_64-pc-linux-gnu
arch x86_64
os linux-gnu
system x86_64, linux-gnu
status
major 3
minor 3.2
year 2016
month 10
day 31
svn rev 71607
language R
version.string R version 3.3.2 (2016-10-31)
nickname Sincere Pumpkin Patch
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