Cython 1

Use your knowledge of Cython to convert the nbody_opt.py program you wrote in Assignment 3 into a Cython program. Pay particular attention to the following:

• Add cdef declarations for all variables
• Use C types in function parameter declarations
• Declare NumPy arrays if you used them, and use efficient indexing

Place the resulting code in a file called nbody_cython.pyx.

Cython provides a module called pyximport for importing .pyx files directly. This module will load and compile the Cython code automatically for you. Use the following commands from IPython or Jupyter in order to load the nbody_cython.pyx module:

%load_ext Cython
import pyximport
pyximport.install()

At this point you should be able to load your Cython program using the normal import statement:

import nbody_cython

When you are satisfied that your program is working, commit it to the same repository you used in Assignment 3