Sun, 21 Jun 2026

RcppArmadillo 15.4.0-1 on CRAN: New Upstream Minor

armadillo image

Armadillo is a powerful and expressive C++ template library for linear algebra and scientific computing. It aims towards a good balance between speed and ease of use, has a syntax deliberately close to Matlab, and is useful for algorithm development directly in C++, or quick conversion of research code into production environments. RcppArmadillo integrates this library with the R environment and language–and is widely used by (currently) 1282 other packages on CRAN, downloaded 47.1 million times (per the partial logs from the cloud mirrors of CRAN), and the CSDA paper (preprint / vignette) by Conrad and myself has been cited 697 times according to Google Scholar.

This versions updates to the 15.4.0 upstream Armadillo release made on Thursday. We had run a complete reverse-dependency check leading up to it, asserting there were no issues with packages dependent on it. As it sometimes goes with that many packages involved, one CRAN package reported one test failure. And it turned out to be both unrelated and pre-existing. But sorting this out over one round of email delayed things by a day. And then I went cycling for a good cause so this announcement post comes a little later than usual. The package has also been updated for Debian, built for r2u, and by now also at CRAN for the different binary releases.

All changes since the last CRAN release follow.

Changes in RcppArmadillo version 15.4.0-1 (2026-06-17)

  • Upgraded to Armadillo release 15.4.0 (Medium Roast Agave)

    • Added fill::nan, fill::pos_inf, fill::neg_inf as optional fill forms for the Mat class

    • Added .push_back() for appending elements to vectors

    • Faster handling of find() within .elem()

    • Faster element-wise min() and max()

    • Faster conv_to when element types of input and output objects are the same

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

This post by Dirk Eddelbuettel originated on his Thinking inside the box blog. If you like this or other open-source work I do, you can sponsor me at GitHub. You can also sponsor my Tour de Shore 2026 ride in support of the Maywood Fine Arts Center.

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