The Stan Math Library is a C++, reverse-mode automatic differentiation library designed to be usable, extensive and extensible, efficient, scalable, stable, portable, and redistributable in order to facilitate the construction and utilization of algorithms that utilize derivatives.

The Stan Math Library is licensed under the new BSD license.

In order to run Stan Math, you must make available the following two libraries on which it depends:

• Boost (version 1.58): Boost Home Page
• Eigen (version 3.24): Eigen Home Page

These should be downloaded and unpacked into directories where they can be read.

Only these two versions of the dependent libraries have been tested with Stan Math.

The Stan Math Library is a header-only C++ library.

A simple hello world program using Stan Math is as follows:

#include <stan/math.hpp>
#include <iostream>

int main() {
  std::cout << "log normal(1 | 2, 3)=" 
            << stan::math::normal_log(1, 2, 3) 
            << std::endl;
}

If this is in the file /path/to/foo/foo.cpp, then you can compile and run this with something like this, with the path/to business replaced with actual paths:

> cd /path/to/foo
> clang++ -I /path/to/stan -I /path/to/Eigen -I /path/to/boost foo.cpp
> ./a.out
log normal(1 | 2, 3)=-2.07311

The -I includes point to the three necessary includes:

• the Stan Math library: the path is to the source directory that contains stan as a subdirectory
• the Eigen C++ matrix library: this path is to the source directory that contains Eigen as a subdirectory
• the Boost C++ library: this path is to the source directory that contains boost as a subdirectory

Note that the paths should not include the final directories stan, Eigen, or boost on the paths. An example of a real instantiation:

clang++ -I ~/stan-dev/math -I ~/stan/lib/eigen_3.2.4/ -I ~/stan/lib/boost_1.58.0/ foo.cpp

The following directories all exist below the links given to -I: ~/stan-dev/math/stan and ~/stan/lib/eigen_3.2.4/Eigen and ~stan/lib/boost_1.58.0/boost.

There's nothing special about clang++ --- the g++ compiler behaves the same way. You'll need to modify the commands for other compilers, which will need to be up-to-date enough to compile the Stan Math Library.