HEALPix Files

This package implements a small subset of routines for working with the
HEALPix tesselation of the sphere.

For information about HEALPix, see the publication by
K.M. Gorski et al., 2005, Ap.J., 622, p.759
(http://adsabs.harvard.edu/abs/2005ApJ...622..759G)
More comprehensive software packages supporting HEALPix, as well as extensive
documentation and references, are available at
https://healpix.sourceforge.io/.


Compilation
===========

gcc -O2 healpix_bare.c -std=c99 test.c -lm
clang -O2 healpix_bare.c -std=c99 test.c -lm
icc -O2 healpix_bare.c -std=c99 test.c -lm


Notes
=====

This package is designed to cover a small set of frequently used HEALPix-related
routines, which are implemented with a focus on robustness, accuracy and clarity.
They have good performance, but are not heavily tuned to keep the code simple -
the full-featured, GPL-licensed Healpix Fortran and C++ libraries (available
via the link above) will be more efficient in most situations.

The motivation for this package is to give developers of BSD-licensed
Healpix-related codes a reliable starting point, so that they don't have to
re-implement the central algorithms (like conversions between pixel index and
angular coordinates), which are nontrivial to do correctly for all corner cases.


Acknowledgements
================

If you are using this code in your own packages, please consider citing
the original paper in your publications:

K.M. Gorski et al., 2005, Ap.J., 622, p.759
(http://adsabs.harvard.edu/abs/2005ApJ...622..759G)