SHTns  2.6.3
High performance Spherical Harmonic Transform for numerical simulations.

SHTns is a high performance library for Spherical Harmonic Transform written in C, aimed at numerical simulation (fluid flows, mhd, ...) in spherical geometries.
Main features :

Using DCT acceleration and other classical optimizations, it is intended to be very fast.

It requires the FFTW library for Fast Fourier Transforms.

If you use SHTns for research work, please cite the paper: Efficient Spherical Harmonic Transforms aimed at pseudo-spectral numerical simulations, also available from arXiv.

If you accept the open source CeCILL License (GPL compatible french License), you can download SHTns.

Please report bugs and feature request on the issue tracker.

See also
shtns.h for the definitions of variables, macros and functions.
The example programs (in Fortran , C and Python ) to get started.
The organisation of data used by SHTns is described in Spatial data layouts and grids used by SHTns.
The description of Optimizations implemented in SHTns.
SHTns is written by Nathanael Schaeffer (CNRS). Email: