Sun, 04 Jun 2017

RcppArmadillo 0.7.900.2.0

The new RcppArmadillo release 0.7.900.2.0 is now on CRAN, and the Debian package was just updated as well.

Armadillo is a powerful and expressive C++ template library for linear algebra aiming towards a good balance between speed and ease of use with a syntax deliberately close to a Matlab. RcppArmadillo integrates this library with the R environment and language--and is widely used by (currently) 350 other packages on CRAN---an increase of 32 since the last CRAN release of 0.7.800.2.0 in April!

With the 7.900.* series of Armadillo, Conrad has started to more fully utilize OpenMP (also see Wikipedia on OpenMP) for operations that can be parallelized. To use this in your package you need to update its src/Makevars{,.win} file similarly to what the skeleton default now uses

PKG_CXXFLAGS = $(SHLIB_OPENMP_CXXFLAGS) 
PKG_LIBS = $(SHLIB_OPENMP_CFLAGS) $(LAPACK_LIBS) $(BLAS_LIBS) $(FLIBS)

and you may want to enable C++11 while you are at it---though this may pose issues with older-than-ancient RHEL installations which are still (way too) pervasive so we do not do it by default (yet).

Here, we once again rely on the build infrastructure automagically provided by R itself: if and when OpenMP is available, R will use it via $(SHLIB_OPENMP_CXXFLAGS) etc; see the fine WRE manual for details. That said, some operating systems make this harder than other, and macOS usually takes the crown. See for example this blog post by James for surviving in that environment. I am a little short of details because on Linux these things just work, and have for well over a decade. The rcpp-devel mailing list will be the best place for questions.

Changes in this release relative to the previous CRAN release are as follows:

Changes in RcppArmadillo version 0.7.900.2.0 (2017-06-02)

• Upgraded to Armadillo release 7.900.2 (Evil Banana Republic)

  • Expanded clamp() to handle cubes

  • Computationally expensive element-wise functions (such as exp(), log(), cos(), etc) can now be automatically sped up via OpenMP; this requires a C++11/C++14 compiler with OpenMP 3.0+ support for GCC and clang compilers

  • One caveat: when using GCC, use of -march=native in conjunction with -fopenmp may lead to speed regressions on recent processors

• Added gcc 7 to support compiler check (James Balamuta in #128 addressing #126).

• A unit test helper function for rmultinom was corrected (#133).

• OpenMP support was added to the skeleton helper in inline.R

Courtesy of CRANberries, there is a diffstat report. More detailed information is on the RcppArmadillo page. Questions, comments etc should go to the rcpp-devel mailing list off the R-Forge page.

This post by Dirk Eddelbuettel originated on his Thinking inside the box blog. Please report excessive re-aggregation in third-party for-profit settings.

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