On Sat, Nov 19, 2022 at 3:50 AM Daniel Schmitz < danielschmitzsiegen@googlemail.com> wrote:
Hi again everyone,
the first milestones proposed here have been implemented: - sampling from the hypersphere - directional sample statistics (direction mean and mean resultant length)
I would like to propose to further add the most commonly used analogue of the normal distribution on the hypersphere: the von Mises-Fisher distribution <https://en.wikipedia.org/wiki/Von_Mises%E2%80%93Fisher_distribution> (vMF). A reference implementations for sampling from it is available in geomstats <https://github.com/geomstats/geomstats/blob/f30c491a6da8cab38be48029d09eda2b...> and fitting and evaluating pdf/logpdf should not be too difficult to implement by ourselves.
Having worked with directional data a lot, I have seen many people struggle with these distributions. I do not think that all kinds of spherical distributions should become part of SciPy, but the vMF is so fundamental that it would be very valuable to the general community.
I think that's reasonable. -- Robert Kern