Le 22/11/12 13:42, JJ Allaire a écrit :
Would something like this work? (Romain you probably know best whether
this will actually work out over a large range of scenarios as well as
if the std::string specialization would work)
#include <Rcpp.h>
using namespace Rcpp;
template<int RTYPE>
RObject unique_generic(RObject x) {
Vector<RTYPE> vector = as<Vector<RTYPE> >(x);
std::tr1::unordered_set<typename Vector<RTYPE>::stored_type >
set(vector.begin(), vector.end());
return wrap(set);
}
template<> RObject unique_generic<CHARSXP>(RObject x) {
// TODO: appropriate specialization for CHARSXP (std::string)
return x;
}
#define DISPATCH_METHOD(method, x) \
switch(x.sexp_type()) { \
case REALSXP: \
return method<REALSXP>(x); \
case INTSXP: \
return method<INTSXP>(x); \
case CHARSXP: \
return method<CHARSXP>(x); \
case LGLSXP: \
return method<LGLSXP>(x); \
default: \
Rf_error("Unsupported type"); \
return x; \
}
// [[Rcpp::export]]
RObject unique2(RObject x) {
DISPATCH_METHOD(unique_generic, x)
}
/*** R
unique2(c(1.0,2.4,3.3,3.3,3.3,3.3,2,2,6))
unique2(c(1,5,5,6,7))
*/
the case CHARSXP is not going to be useful. You need to handle the
STRSXP case.
I've been looking at related things this morning. Right now, I can
propose this:
#include <Rcpp.h>
using namespace Rcpp;
template<int RTYPE>
SEXP unique_generic( const Vector<RTYPE> vector ) {
typedef RCPP_UNORDERED_SET< typename Vector<RTYPE>::stored_type >
SET ;
SET set(vector.begin(), vector.end());
Vector<RTYPE> out( set.size() ) ;
std::copy( set.begin(), set.end(), out.begin() ) ;
return out ;
}
#define DISPATCH_METHOD(method, x) \
switch( TYPEOF(x) ){ \
case REALSXP: \
return method<REALSXP>(x); \
case INTSXP: \
return method<INTSXP>(x); \
case STRSXP: \
return method<STRSXP>(x); \
case LGLSXP: \
return method<LGLSXP>(x); \
default: \
Rf_error("Unsupported type"); \
return x; \
}
// [[Rcpp::export]]
SEXP unique2(SEXP x) {
DISPATCH_METHOD(unique_generic, x)
}
I'm not fully satisfied with this, and I'd like to have this instead:
template<int RTYPE>
SEXP unique_generic( const Vector<RTYPE> vector ) {
typedef RCPP_UNORDERED_SET< typename Vector<RTYPE>::stored_type >
SET ;
SET set(vector.begin(), vector.end());
return Vector<RTYPE> out( set.begin(), set.end() ) ;
}
But the range constructor for Vector does not do what I want. I'm
looking into it.
Romain
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