fn phase_partition(v: f64, width: f64, partitions: usize) -> Option<usize>Expand description
Which phase partition a voxel falls in, or None if it has no usable phase.
Clamped rather than asserted: the caller is documented to supply phase in
[-π, π], and exactly +π would otherwise fall off the end of the last bin.
Anything that strayed further out joins the nearest bin, which keeps the voxel in
play — any region it lands in still merges on its measured phase differences.