Rcpp Version 0.12.12
convolve9_cpp.cpp
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1 // -*- mode: C++; c-indent-level: 4; c-basic-offset: 4; tab-width: 8 -*-
2 
3 // this version expands convolve8_cpp by making Vec mimic the structure of
4 // NumericVector. It peforms well, so this is is not the structure of
5 // NumericVector that is the problem. So what is it then ?
6 //
7 // could it be because NumericVector is in a different library than
8 // this code, so that operator[] is not inlined ?
9 //
10 // clues:
11 // - http://infocenter.arm.com/help/index.jsp?topic=/com.arm.doc.faqs/ka3538.html
12 
13 #include <Rcpp.h>
14 
15 class Cache{
16 public:
17  typedef double& proxy ;
18  typedef double* iterator ;
19 
20  Cache( iterator data_) : data(data_){}
21 
22  inline proxy ref(int i){ return data[i] ; }
23  inline proxy ref(int i) const { return data[i] ; }
24 
25 private:
26  iterator data ;
27 } ;
28 
29 class Vec {
30 public:
31  typedef double& proxy ;
32 
33  Vec( double* data_ ) : cache(data_){}
34  inline proxy operator[]( int i){ return cache.ref(i) ; }
35  inline proxy operator[]( int i) const { return cache.ref(i) ; }
36 
37 private:
38  Cache cache ;
39 } ;
40 
41 
42 RcppExport SEXP convolve9cpp(SEXP a, SEXP b){
43  Rcpp::NumericVector xa(a);
44  Rcpp::NumericVector xb(b);
45  int n_xa = xa.size() ;
46  int n_xb = xb.size() ;
47  int nab = n_xa + n_xb - 1;
48  Rcpp::NumericVector xab(nab);
49 
50  Vec vab(xab.begin()), va(xa.begin()), vb(xb.begin()) ;
51 
52  for (int i = 0; i < n_xa; i++)
53  for (int j = 0; j < n_xb; j++)
54  vab[i + j] += va[i] * vb[j];
55 
56  return xab ;
57 }
58 
59 #include "loopmacro.h"
61 
proxy ref(int i)
#define LOOPMACRO_CPP(name)
Definition: loopmacro.h:12
double * iterator
proxy operator[](int i) const
iterator data
#define RcppExport
Definition: RcppCommon.h:129
Cache(iterator data_)
R_xlen_t size() const
Definition: Vector.h:274
RcppExport SEXP convolve9cpp(SEXP a, SEXP b)
Vec(double *data_)
proxy ref(int i) const
double & proxy
iterator begin()
Definition: Vector.h:332
double & proxy
proxy operator[](int i)