RcppExamples/src/MatrixExample.cpp at master · cran/RcppExamples

43 lines (36 loc) · 1.56 KB

// -*- mode: C++; c-indent-level: 4; c-basic-offset: 4; indent-tabs-mode: nil; -*-

// RcppMatrixExample.cpp: RcppMatrix example

// This file is part of RcppExamples.

// RcppExamples is free software: you can redistribute it and/or modify it

// under the terms of the GNU General Public License as published by

// the Free Software Foundation, either version 2 of the License, or

// (at your option) any later version.

// RcppExamples is distributed in the hope that it will be useful, but

// WITHOUT ANY WARRANTY; without even the implied warranty of

// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the

// GNU General Public License for more details.

// You should have received a copy of the GNU General Public License

// along with RcppExamples. If not, see <http://www.gnu.org/licenses/>.

#include <Rcpp.h>

#include <cmath>

// suncc needs help to disambiguate between sqrt( float ) and sqrt(double)

inline static double sqrt_double(double x) { return ::sqrt(x); }

using namespace Rcpp;

// [[Rcpp::export]]

List MatrixExample(const NumericMatrix & orig) {

NumericMatrix mat(orig.nrow(), orig.ncol());

// we could query size via

// int n = mat.nrow(), k=mat.ncol();

// and loop over the elements, but using the STL is so much nicer

// so we use a STL transform() algorithm on each element

std::transform(orig.begin(), orig.end(), mat.begin(), sqrt_double);

return List::create(Named("result") = mat,

Named("original") = orig);

}

Provide feedback