Boost is a C++ library that can interface with Python. Download it from http://www.boost.org/users/download/. The latest Boost version at the time of writing was 1.56.0. The easiest but also slowest installation method involves the following commands:

$ ./bootstrap.sh --prefix=/path/to/boost
$ ./b2 install

The prefix argument specifies the installation directory. In this example, we will assume that Boost was installed under the user's home directory in a directory called Boost (such as ~/Boost). In this directory, a lib and include directory will be created. For Unix and Linux, it is useful to run the following command:

export LD_LIBRARY_PATH=$HOME/Boost/lib:${LD_LIBRARY_PATH}

On Mac OS X, set the following environment variable:

export DYLD_LIBRARY_PATH=$HOME/Boost/lib

Redefine a rain summation function as given in the boost_rain.cpp file in this book's code bundle:

#include <boost/python.hpp>

double sum_rain(boost::python::list rain, int len) {

  double...