Chapter 20
Package structure

The NekPy wrapper is designed to mimic the library structure of Nektar++, with directories for the LibUtilities, SpatialDomains and StdRegions libraries. This is a deliberate design decision, so that classes and definitions in Nektar++ can be easily located inside NekPy.

There are also some other directories and files:

• LibUtilities/Python/NekPyConfig.hpp is a convenience header that all .cpp files should import. It sets appropriate namespaces for boost::python and boost::python::numpy, depending on whether the Boost.NumPy library was compiled or is included in Boost,
• cmake/python contains templates for init.py and setup.py files which every Python package should contain,
• cmake/ThirdPartyPython.cmake is a CMake configuration file which searches for Boost.Python and prepares make targets for installing NekPy.

Figure 20.1 shows the location of Python wrapper files within Nektar++ structure. Every sub-module of Nektar++ hosts an additional folder for Python files and the structure of the Python folder mimics the structure of the sub-module itself, as shown on the left of the figure with LibUtilities sub-module. Individual .cpp files, such as Expansion.cpp contain the wrappers for classes and methods from corresponding Nektar++ library files whereas .cpp files named after sub-modules (e.g. LibUtilities.cpp) contain BOOST_PYTHON_MODULE definitions which create package modules (e.g. NekPy.LibUtilities).