vignettes/children/comparison-with-rstan.md

In stan-dev/cmdstanr: R Interface to 'CmdStan'

Different ways of interfacing with Stan's C++

The RStan interface (rstan package) is an in-memory interface to Stan and relies on R packages like Rcpp and inline to call C++ code from R. On the other hand, the CmdStanR interface does not directly call any C++ code from R, instead relying on the CmdStan interface behind the scenes for compilation, running algorithms, and writing results to output files.

Advantages of RStan

• Allows other developers to distribute R packages with pre-compiled Stan programs (like rstanarm) on CRAN. (Note: As of 2023, this can mostly be achieved with CmdStanR as well. See Developing using CmdStanR.)

• Avoids use of R6 classes, which may result in more familiar syntax for many R users.

• CRAN binaries available for Mac and Windows.

Advantages of CmdStanR

• Compatible with latest versions of Stan. Keeping up with Stan releases is complicated for RStan, often requiring non-trivial changes to the rstan package and new CRAN releases of both rstan and StanHeaders. With CmdStanR the latest improvements in Stan will be available from R immediately after updating CmdStan using cmdstanr::install_cmdstan().

• Running Stan via external processes results in fewer unexpected crashes, especially in RStudio.

• Less memory overhead.

• More permissive license. RStan uses the GPL-3 license while the license for CmdStanR is BSD-3, which is a bit more permissive and is the same license used for CmdStan and the Stan C++ source code.

stan-dev/cmdstanr documentation built on April 12, 2025, 8:40 p.m.