[R] Dispatching on a dgCMatrix does not work.
Martin Morgan
mtmorgan at fhcrc.org
Tue Dec 11 16:33:27 CET 2012
On 12/11/2012 01:46 PM, Søren Højsgaard wrote:
> I represent a graph as an adjacency matrix of class "dgCMatrix" (from the Matrix package).
>
>> xx
> 5 x 5 sparse Matrix of class "dgCMatrix"
> a b c d e
> a . 1 1 . .
> b 1 . 1 . .
> c 1 1 . 1 1
> d . . 1 . 1
> e . . 1 1 .
>
> To check if the matrix defines and undirected graph, I have made the following functions/methods:
>
> is.UG <- function (object) {
> UseMethod("is.UG")
> }
> is.UG.dgCMatrix <- function (object) {
> is.adjMAT(object) && (max(abs(t(object) - object)) == 0)
> }
>
> Note: 1) is.adjMAT is homegrown and 2) I know there is an "isSymmetric" method, but I can't get that to work either. These functions are in a package and when I load the package I get:
>
>> is.UG(xx)
> Error in t.default(object) : argument is not a matrix
You take the transpose of a dgCMatrix. This is supposed to use one of the
showMethods('t') from Matrix, but I guess your package NAMESPACE file does not
importMethodsFrom(Matrix, t) or similar.
Martin Morgan
>
>> is.UG.dgCMatrix(xx)
> Error in t.default(object) : argument is not a matrix
>
> Interestingly, if I copy and past the definitions above into an R-session things do work:
>
>> is.UG <- function (object) {
> + UseMethod("is.UG")
> + }
>> is.UG.dgCMatrix <- function (object) {
> + is.adjMAT(object) && (max(abs(t(object) - object)) == 0)
> + }
>>
>> is.UG(xx)
> [1] TRUE
>> is.UG.dgCMatrix(xx)
> [1] TRUE
>
> Can anyone help here?
>
> Best regards
> Søren
>
>
> xx <- new("dgCMatrix"
> , i = c(1L, 2L, 0L, 2L, 0L, 1L, 3L, 4L, 2L, 4L, 2L, 3L)
> , p = c(0L, 2L, 4L, 8L, 10L, 12L)
> , Dim = c(5L, 5L)
> , Dimnames = list(c("a", "b", "c", "d", "e"), c("a", "b", "c", "d", "e"))
> , x = c(1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1)
> , factors = list()
>
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