Installing Rcplex in RStudio

This is an update to a previous post ("Installing Rcplex and cplexAPI"). Rcplex is a interface from R to the CPLEX optimization solver. A recent release (it's now at version 0.3-5) has made installation and updating much easier (no hacking of installer code required), provided you configure your environment correctly.

I use the RStudio IDE for almost everything related to R, including updating packages. A recent list of packages waiting to be updated included Rcplex 0.3-4, but when I told RStudio to update them all it balked at Rcplex. The workaround is actually quite simple. What follows is how I got to work in Linux Mint, but the same steps should work with any Linux distribution and I assume can be modified to work on Windows or Mac OS.

1. Find where the CPLEX binary lives. In my case, the path was "/home/paul/<stuff>/CPLEX_Studio201/cplex/bin/x86-64_linux/cplex".
2. In a terminal, create an environment variable CPLEX_BIN containing that path (unless you already have one). This can be done using the export command, as in "export CPLEX_BIN=/home/paul/<stuff>/CPLEX_Studio201/cplex/bin/x86-64_linux/cplex". Note that what I am exporting includes the name of the executable (that last "cplex"), not just the path to it. (I goofed on my first try by just specifying the path.)
3. Now invoke RStudio from the terminal and do the package update (or installation if you are getting it for the first time) as normal.

If you are not an RStudio user, you can install or update the package manually from a terminal by issuing the same export command followed by "R CMD INSTALL <path to download>/Rcplex_0.3-5.tar.gz" (updating the version number as necessary).

This was much less painful than previous installations. Thanks to the developers for maintaining the package and updating the installation scripts!

Update (04/23/2023): A recent update to the base R package (to 4.3.0) forced me to reinstall Rcplex, and of course I ran into problems. The current version of Rcplex in CRAN is 0.3-6. I followed the steps described above, and the C compiler barfed up some messages about multiple definitions of things and exited with an error code. Luckily, in the course of searching for explanations of the errors and fixes I tripped over the development page for Rcplex, where I found version 0.3-7, which had been released just a few days ago. That version installed correctly. Big thanks to the developers for continuing to maintain it.