Test environments local OS X install, R 4.1.0 Fedora Linux, R-devel, clang, gfortran (rhub.io) Ubuntu Linux 16.04 LTS, R-release, GCC (rhub.io) Windows Server 2008 R2 SP1, R-devel, 32/64 bit (rhub.io) R CMD check results There were no ERRORs, WARNINGs or NOTEs. Downstream dependencies None