R bindings for the xtensor C++ multi-dimensional array library.

• xtensor is a C++ library for multi-dimensional arrays enabling numpy-style broadcasting and lazy computing.

• xtensor-r enables inplace use of R arrays in C++ with all the benefits from xtensor

  • C++ universal functions and broadcasting
  • STL - compliant APIs.
  • A broad coverage of numpy APIs (see the numpy to xtensor cheat sheet).

xtensor-r can be used either to author C++ extensions for R with Rcpp, or applications that embed the R interpreter with RInside.

Example

#include <numeric>                    // Standard library import for std::accumulate
#define STRICT_R_HEADERS              // Otherwise a PI macro is defined in R
#include "xtensor/xmath.hpp"          // xtensor import for the C++ universal functions
#include "xtensor-r/rarray.hpp"       // R bindings

#include <Rcpp.h>

using namespace Rcpp;

// [[Rcpp::plugins(cpp14)]]

// [[Rcpp::export]]
double sum_of_sines(xt::rarray<double>& m)
{
    auto sines = xt::sin(m);  // sines does not actually hold values.
    return std::accumulate(sines.cbegin(), sines.cend(), 0.0);
}

v <- matrix(0:14, nrow=3, ncol=5)
s <- sum_of_sines(v)
s

# prints 1.2853996391883833

Installation

xtensor-r has been packaged for CRAN (The Comprehensive R Archive Network). It can be installed

install.packages("xtensor")

or from the repository using devtools:

devtools::install_github("QuantStack/xtensor-r", ref="package")

Installation from Sources

xtensor-r is primarily a C++ library that can be installed classically using cmake in any installation prefix. For example, on unix systems

cmake -D CMAKE_INSTALL_PREFIX=/prefix/path/ .
make
make install

A tarball for the R package archive network (CRAN) can be generated.

mkdir build
cd build
cmake -D CMAKE_INSTALL_PREFIX=/prefix/path/ ..
make
make cran

The generated tarball vendors the headers of the core xtensor library. It can be installed with

install.packages('xtensor_0.9.0-0.tar.gz')

The package can be tested with a simple function call.

library('xtensor')
xtensor::rcpp_hello_xtensor(4:12)

Documentation

To get started with using xtensor-r, check out the full documentation

http://xtensor-r.readthedocs.io/

Dependencies on xtensor and Rcpp

xtensor-r depends on the xtensor and Rcpp libraries

• Core xtensor headers are vendored in the CRAN package.
• When using the conda, or debian package managers, xtensor-r has a dependency on xtensor.

License

We use a shared copyright model that enables all contributors to maintain the copyright on their contributions.

This software is licensed under the BSD-3-Clause license. See the LICENSE file for details.