Romain,
Perhaps I now see the light at the end of the tunnel (hope it is not a train
comming against me!): If I understand this correctly, the following
> template <int RTYPE>
> Matrix<RTYPE> vec2matrix2(Vector<RTYPE> x, int nrow, int ncol) {
> return Matrix<RTYPE>(nrow, ncol, x.begin()); }
should do the dispatching properly if I call vec2matrix2 from a c++ function.
Right? And all the other bells and whistles are merely to be able to call the
function from R?
Cheers
Søren
-----Original Message-----
From: Romain Francois [mailto:[email protected]]
Sent: 31. maj 2013 11:37
To: Søren Højsgaard
Cc: [email protected]
Subject: Re: [Rcpp-devel] Turning a vector into a matrix
Ah ok, so you want to use this from R, I would suggest to Rcpp::export a
dispatcher, something like this:
#include <Rcpp.h>
using namespace Rcpp ;
// the template
template <int RTYPE>
Matrix<RTYPE> vec2matrix__impl(Vector<RTYPE> x, int nrow, int ncol) {
return Matrix<RTYPE>(nrow, ncol, x.begin()); }
// the exported dispatcher,used from R
// [[Rcpp::export]]
SEXP vec2matrix(SEXP x, int nrow, int ncol){
switch( TYPEOF(x) ){
case REALSXP: return vec2matrix__impl( NumericVector(x), nrow, ncol ) ;
case INTSXP: return vec2matrix__impl( IntegerVector(x), nrow, ncol ) ;
// ... add other cases you want to handle
default:
return R_NilValue ;
// .. or do whatever
}
}
/*** R
vec2matrix( 1:10, 2, 5 )
vec2matrix( rnorm(10), 2, 5 )
***/
Romain
Le 31/05/13 11:30, Søren Højsgaard a écrit :
> Romain,
>
> I actually already tried this in my file util.cpp but can't get it to work:
>
> #include <Rcpp.h>
>
> using namespace Rcpp;
>
> // [[Rcpp::export]]
> NumericMatrix vec2matrix(NumericVector x, int nrow, int ncol) {
> return NumericMatrix(nrow, ncol, x.begin()); }
>
> // [[Rcpp::export]]
> template <int RTYPE>
> Matrix<RTYPE> vec2matrix2(Vector<RTYPE> x, int nrow, int ncol) {
> return Matrix<RTYPE>(nrow, ncol, x.begin()); }
>
> Any thoughts?
Don't Rcpp::export templates.
> Søren
>
>
>
>> Rcpp::sourceCpp('./util.cpp')
> g++ -m64 -I"C:/programs/R/current/include" -DNDEBUG
> -I"C:/programs/R/current/library/Rcpp/include"
> -I"d:/RCompile/CRANpkg/extralibs64/local/include" -O2 -Wall -mtune=core2
> -c util.cpp -o util.o util.cpp: In function 'SEXPREC*
> sourceCpp_50379_vec2matrix2(SEXP, SEXP, SEXP)': util.cpp:75:12: error:
> 'RTYPE' was not declared in this scope util.cpp:75:17: error: template
> argument 1 is invalid util.cpp:75:21: error: invalid type in declaration
> before '=' token util.cpp:75:44: error: could not convert template argument
> 'RTYPE' to 'int' util.cpp:75:53: error: no matching function for call to
> 'as(SEXPREC*&)' util.cpp:75:53: note: candidate is:
> C:/programs/R/current/library/Rcpp/include/Rcpp/as.h:125:29: note:
> template<class T> T Rcpp::as(SEXP) util.cpp:78:5: error: a template
> declaration cannot appear at block scope util.cpp:79:5: error: expected ';'
> before 'return' util.cpp:75:19: warning: unused variable 'x'
> [-Wunused-variable] util.cpp:76:9: warning: unused variable 'nro
w' [-Wunu
sed-variable] util.cpp:77:9: warning: unused variable 'ncol'
[-Wunused-variable] make: *** [util.o] Error 1
> Error in Rcpp::sourceCpp("./util.cpp") :
> Error 1 occurred building shared library.
>
>
>
>
>
>
> -----Original Message-----
> From: [email protected]
> [mailto:[email protected]] On Behalf Of
> Romain Francois
> Sent: 31. maj 2013 11:22
> To: [email protected]
> Subject: Re: [Rcpp-devel] Turning a vector into a matrix
>
> Hello Søren,
>
> This is easy templating:
>
> template <int RTYPE>
> Matrix<RTYPE> vec2matrix(Vector<RTYPE> x, int nrow, int ncol) {
> return Matrix<RTYPE>(nrow, ncol, x.begin()); }
>
> will work for NumericVector, IntegerVector, CharacterVector, ...
>
> Romain
>
> Le 31/05/13 11:08, Søren Højsgaard a écrit :
>> Dear all,
>>
>> Dirk: Thanks for the reply :).
>>
>> I shall dare to ask a "bonus question": I've played around with templating
>> so that I get the right output type. I know (thanks to an earlier reply by
>> Romain) how to do so using SEXP's but if I am constructing a utility
>> function to be used on c++ objects, I can't that to work. What I am after
>> should mimic the following such that the output type is determined by the
>> input type:
>>
>> NumericMatrix vec2matrix(NumericVector x, int nrow, int ncol) {
>> return NumericMatrix(nrow, ncol, x.begin()); }
>>
>> IntegerMatrix vec2matrix(IntegerVector x, int nrow, int ncol) {
>> return IntegerMatrix(nrow, ncol, x.begin()); }
>>
>> Any help would be more than welcome.
>>
>> Best regards
>> Søren
>>
>>
>>
>>
>>
>> -----Original Message-----
>> From: Dirk Eddelbuettel [mailto:[email protected]]
>> Sent: 31. maj 2013 03:01
>> To: Søren Højsgaard
>> Cc: [email protected]
>> Subject: Re: [Rcpp-devel] Turning a vector into a matrix
>>
>>
>> Soren,
>>
>> You missed the most appropriate constructor:
>>
>> template <typename Iterator>
>> Matrix( const int& nrows_, const int& ncols, Iterator start ) ;
>>
>> With that we just do this:
>>
>> R> Rcpp::sourceCpp('/tmp/soren.cpp')
>> R> soren(1:4,2,2)
>> [,1] [,2]
>> [1,] 1 3
>> [2,] 2 4
>> R>
>>
>> and the file soren.cpp is below.
>>
>> Dirk
>>
>>
>> #include <Rcpp.h>
>>
>> using namespace Rcpp;
>>
>> // [[Rcpp::export]]
>> NumericMatrix soren(NumericVector x, int n, int k) {
>> return NumericMatrix(n, k, x.begin()); }
--
Romain Francois
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