NAME

       Gyotoy - visualize one geodesic in Kerr metric

SYNOPSIS

       gyotoy [input.xml]

DESCRIPTION

       Gyoto  is  a  framework  for computing geodesics in curved space-times. The gyotoy utility
       program uses this framework to compute and display a single geodesic (the trajectory of  a
       massive or mass-less particle) in Kerr metric.

       gyotoy  takes  as  optional argument a scenery description in XML format (input.xml). This
       scenery must contain a Astrobj section of kind Star. Alternatively, a default  scenery  is
       loaded.

       The  user can then interactively select initial parameters and redraw the geodesic as many
       time as needed. the Projection parameters allow rotating the view and various menu entries
       are rather self-explanatory. Entries in the File menu allow saving the display as an image
       file, saving the parameters as an XML description, or saving the geodesic's coordinates in
       an ASCII file.

       gyotoy is only a small utility to visualise a single geodesic. It can also be invoked from
       the yorick(1) prompt for building more complex graphics and for scripting. Have a look  at
       the gyoto.i and gyotoy.i files in yorick's Y_SITE directory.

       A  companion  program,  gyoto(1),  can  be  used  to compute an entire Gyoto scenery using
       relativistic ray-tracing.

ENVIRONMENT

       GYOTO_PLUGINS
              The "Star" object in Gyoto is part of the standard plug-in.  If  the  GYOTO_PLUGINS
              environment  variable  is set, it must contain at least "stdplug" for gyotoy to run
              properly.

AUTHOR

       Thibaut Paumard <thibaut.paumard@obspm.fr> wrote this manual.

SEE ALSO

       gyoto(1), yorick(1)