OnWorks favicon

gyotoy - Online in the Cloud

Run gyotoy in OnWorks free hosting provider over Ubuntu Online, Fedora Online, Windows online emulator or MAC OS online emulator

This is the command gyotoy that can be run in the OnWorks free hosting provider using one of our multiple free online workstations such as Ubuntu Online, Fedora Online, Windows online emulator or MAC OS online emulator



Gyotoy - visualize one geodesic in Kerr metric


gyotoy [input.xml]


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

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.


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

Use gyotoy online using onworks.net services