This notebook demonstrates an implementation of the Barnes Hut algorithm in Julia, originally done for 18-335 at MIT.
You can read the accompanying paper Octrees Quadtrees Barnes-Hut for a bit on the implementation and references. The paper surveys the use of Octrees and Quadtrees. Special emphasis is given to the implementation of the Barnes-Hut algorithm and it’s use of trees for n-body simulations. Implementation of this is done in Julia code, using Quadtrees
The function create_bodies is modeled after the explanation provided by Frans Pretorius and Tim Koby. It uses the plummer model to create a toy universe, this model is denser at the center. https://physics.princeton.edu/~fpretori/Nbody/