[R] On-demand importing of a package

[Gábor Csárdi]

Thanks, I have tried that, it does not work, because rowSums() calls
callGeneric():

> Matrix:::rowSums(W)
Error in callGeneric() :
  'callGeneric' must be called from a generic function or method

G.

On Tue, Nov 22, 2011 at 3:20 PM, R. Michael Weylandt
<michael.weylandt at gmail.com> wrote:
> How about calling Matrix's namespace directly?
>
> Matrix:::rowSums()
>
> Michael
>
> On Tue, Nov 22, 2011 at 3:16 PM, Gábor Csárdi <csardi at rmki.kfki.hu> wrote:
>> Dear All,
>>
>> in some functions of my package, I use the Matrix S4 class, as defined
>> in the Matrix package.
>>
>> I don't want to depend on Matrix, however, because my package is
>> perfectly fine without Matrix, most of the functionality does not need
>> Matrix. Matrix is so included in the 'Suggests' line.
>>
>> I load Matrix via require(), from the functions that really need it.
>> This mostly works fine, but I have an issue now that I cannot sort
>> out.
>>
>> If I define a function like this in my package:
>>
>> f <- function() {
>>  require(Matrix)
>>  res <- sparseMatrix(dims=c(5, 5), i=1:5, j=1:5, x=1:5)
>>  y <- rowSums(res)
>>  res / y
>> }
>>
>> then calling it from the R prompt I get
>> Error in rowSums(res) : 'x' must be an array of at least two dimensions
>>
>> which basically means that the rowSums() in the base package is
>> called, not the S4 generic in the Matrix package. Why is that?
>> Is there any way to work around this problem, without depending on Matrix?
>>
>> I am doing this on R 2.14.0, x86_64-apple-darwin9.8.0.
>>
>> Thank You, Best Regards,
>> Gabor
>>
>> --
>> Gabor Csardi <csardi at rmki.kfki.hu>     MTA KFKI RMKI
>>
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>> and provide commented, minimal, self-contained, reproducible code.
>



-- 
Gabor Csardi <csardi at rmki.kfki.hu>     MTA KFKI RMKI