[R] passing a matrix to C++ with .C()?

[Timothy H. Keitt]

Take a look at the ".Call" documentation in the "writing R extensions"
manual. If you mean passing an R matrix to C++, then you will have to
pass the SEXP structure containing the matrix into your C++ code and
manipulate it with internal R functions. If you mean passing a C++
matrix into R, you will have to wrap the pointer and return it from your
C++ code. Note that R will have no idea what to do with the pointer
unless you provide appropriate functions/methods to manipulate it in R.
(I believe the "Matrix" package does just that.)

Tim

On Tue, 2002-05-07 at 01:05, Francisco J Molina wrote:
> It seems that it is possible to pass a matrix to C++ by using .C()
> 
> The R part of the interface should be something like:
> 
> ('C++function', matrix, numberRows, numberColumns )
> 
> ...I guess.
> 
> The C++ part of the interface could be something like
> 
> void C++( double matrix[][], int numberRows, numberColumns )
> 
> but C++ requires to indicate the number of columns, that is, instead of
> matrix[][], it should be double matrix[][ numberColumns ]...
> 
> This does not look like the right thing to do though.
> 
> Can anyone help me with this?
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