A new treecode with variable branching ratio

Abstract

We propose a new hierarchical tree algorithm with high adaptivity to particle distributions for long-range force calculations. This algorithm divides parent cells into k daughter cells by using the k-means algorithm. The tree structure provided by the algorithm is independent of the coordinate system. This method also includes a unique procedure for determining cell sizes adjusted to the particle distribution. Comparing the performance of the algorithm to that of the Barnes-Hut octtree by using gravitational calculations at the same error level, including only the monopole term, we found that the calculation cost was lower, the performance was superior, and the calculation incurred a smaller error.