Hazel (an acronym for HAnle and ZEeman Light) is a computer program for the synthesis and inversion of Stokes profiles caused by the joint action of atomic level polarization and the Hanle and Zeeman effects. It is based on the quantum theory of spectral line polarization, which takes into account rigorously all the relevant physical mechanisms and ingredients: optical pumping, atomic level polarization, level crossings and repulsions, Zeeman, Paschen-Back and Hanle effects. The code is written in standard Fortran 90. Its parameters are passed using four configuration files that can be manually edited. These configuration files are heavily commented, so that their edition should be an easy task. In any case, two front-ends coded in IDL are given as a part of the distribution in order to facilitate a user-friendly execution of the program. A parallel version of the code using Message Passing Interface (MPI) is also available as well as a Python wrapper.
Follow the manual in http://aasensio.github.io/hazel to run the code.