Survey of Parallel A* in Rust

Abstract

A* is one of the most popular Best First Search (BFS) techniques for graphs. It combines the cost-based search of Breadth First Search with a computed heuristic for each node to attempt to locate the goal path faster than traditional Breadth First Search or Depth First Search techniques. However, A* is a sequential algorithm. The standard implementation only runs in one thread. There are a few attempts to get A* to leverage multiple threads. Centralized (SPA*) and Decentralized (DPA*, HDA*) methods are the most standard attempts, with the most unique and modern method being massively-parallel A* (MPA* or GA*). We will attempt an implementation of each in Rust to determine if there is a performance boost, and which one has the best performance.