Parallel spatial indexing for domain discretization

To perform domain discretization efficiently, a data structure that allows for efficient point storage and spatial indexing is required. Such a structure must offer efficient dynamic element insertions and point neighbor lookups. In order to fully utilize the modern CPUs present in state-of-the-art computers, the structure should also allow for multiple threads of execution to simultaneously access and modify the structure in a safe and predictable manner. While many structures exist which allow for simultaneous lookups, most do not allow for simultaneous insertion. In this paper we present Polyp, an indexing data structure which allows for simultaneous multithreaded lookups and insertions of points of arbitrary dimensionality, implemented in C++. We present the approach to thread safety and correctness. We also compare the structure to an existing structure based on nanoflann.