                             ***  GYOTO  ***

       General relativitY Orbit Tracer of Observatoire de Paris

Gyoto aims at providing a framework for computing orbits and
ray-traced images in General relativity. It consists in a library
(libgyoto), utility programs, and a plug-in for the Yorick programing
language.

We request that use of Gyoto in scientific publications be properly
acknowledged. Please cite:

    GYOTO: a new general relativistic ray-tracing code, F. H. Vincent,
    T. Paumard, E. Gourgoulhon & G. Perrin, Classical and Quantum
    Gravity 28, 225011 (2011) [arXiv:1109.4769]

We also request that Gyoto modifications, extensions or plug-ins
leading to a scientific publication be made public as free software
reasonably fast (within one year after publication of the scientific
paper), for instance by contributing it directly to the Gyoto
code base. Contributors will be listed in the relevant source files as
well as in the AUTHORS file in the package.

    Gyoto is Copyright 2011-2012 Thibaut Paumard, Frédéric Vincent (To
    ease reading on non-UTF8 systems, French accents are omitted in
    file headers).

    Gyoto is free software: you can redistribute it and/or modify
    it under the terms of the GNU General Public License as published by
    the Free Software Foundation, either version 3 of the License, or
    (at your option) any later version.

    Gyoto is distributed in the hope that it will be useful,
    but WITHOUT ANY WARRANTY; without even the implied warranty of
    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
    GNU General Public License for more details.

    You should have received a copy of the GNU General Public License
    along with Gyoto.  If not, see <http://www.gnu.org/licenses/>.

Refer to the file INSTALL for building and installing Gyoto.
Specific instructions for Linux/Ubuntu are in the file INSTALL.ubuntu. 

Several sample files are provided in doc/examples. You can ray-trace
those sceneries with:

  gyoto <input-file.xml> <output-file.fits>

FITS files can be read by a variety of free and proprietary
software. See http://heasarc.gsfc.nasa.gov/docs/heasarc/fits.html.

Custom metrics and astronomical objects can be added fairly easily by
implementing them as a Gyoto plug-in. This, of course, requires
knowledge of the C++ language. We don't provide yet a complete guide,
but look at the standard plug-in lib/StdPlug.C which includes the Kerr
metric and the standard objects. The Lorene (numerical) metrics are
also implemented as a plug-in, see lib/LorenePlug.C and
lib/Makefile.lorene.

                        -- Thibaut Paumard, Tue Aug 30 2011.
