Barnes-Hut Algorithm

A Rust implementation of the Barnes-Hut tree in 3 dimensions.

This implementation focuses on the use of Rusts's enumerations to describe multiple coordniate systems, as well as the tree structure that forms the heart of the algorithm.

Description

A detailed discussion on the Barnes-Hut algorithm is given here.

Implementation details

The main components of this implementation are:

• Point <enum>
• Bounds <struct>
• Body <struct>
• BHTree <enum>

There are 3 available coordinate systems to choose from:

• Cartesian : x, y, z
• Cylindrical : r, phi, z
• Spherical : rho, phi, theta

These are determined at the Point level (as variants of the enumeration), and, for the most part, cannot be interchanged. The chosen system is used to describe the limits of the Bounds instances and the centre of mass of the Body instances and tree nodes.

Based on the algorithm, the BHTree enumeration has 3 variants:

• Empty : a tree node with no constituent Body instances
• Node : a tree node with exactly one consitient Body instance
• Nodes : a tree node with child nodes