pub fn radix_sort_by_density(densities: &[f64]) -> Vec<usize>Expand description
Sort particle indices in ascending order of density using a reference sort.
This CPU reference implementation mirrors what a GPU radix sort would do for load-balancing purposes: denser regions can be binned together for more uniform workloads.
Returns a permutation indices such that densities[indices[0\]] <= densities[indices[1\]] ....