GNUMAGIC is a fast eigenvector hybrid look-up table method for the calculation of global and direct irradiance. MAGIC contains a interface for satellite based cloud information provided by the Heliosat meethod. Libradtan has been used to develop GNUMAGIC, in detail for sensitivity studies and the calculation of the look-up tables. The software including documentation is available at:

http://gnu-magic.sourceforge.net or http://sourceforge.net/projects/gnu-magic