44 lines
1.2 KiB
C++
44 lines
1.2 KiB
C++
// -*- mode: C++; c-indent-level: 4; c-basic-offset: 4; tab-width: 8 -*-
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// this version is between the Rcpp_New_ptr and the Rcpp_New_std version
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// test elapsed relative user.self sys.self
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// 5 Rcpp_New_ptr(REPS, a, b) 0.214 1.000000 0.213 0.001
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// 7 Rcpp_New_std_2(REPS, a, b) 0.223 1.042056 0.216 0.006
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// 4 Rcpp_New_std(REPS, a, b) 0.524 2.448598 0.523 0.001
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//
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// so there is some overhead due to creating Vec objects and indexing them
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// but much less than when we index the NumericVector
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#include <Rcpp.h>
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class Vec {
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public:
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Vec( double* data_ ) : data(data_){}
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inline double& operator[]( int i){ return data[i] ; }
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private:
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double* data ;
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} ;
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RcppExport SEXP convolve8cpp(SEXP a, SEXP b){
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Rcpp::NumericVector xa(a);
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Rcpp::NumericVector xb(b);
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int n_xa = xa.size() ;
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int n_xb = xb.size() ;
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int nab = n_xa + n_xb - 1;
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Rcpp::NumericVector xab(nab);
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Vec vab(xab.begin()), va(xa.begin()), vb(xb.begin()) ;
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for (int i = 0; i < n_xa; i++)
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for (int j = 0; j < n_xb; j++)
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vab[i + j] += va[i] * vb[j];
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return xab ;
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}
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#include "loopmacro.h"
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LOOPMACRO_CPP(convolve8cpp)
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