Voyager is a batch mode version of
that processes in parallel a series of snapshots from a simulation.
It shares its code base with Rocketeer and has nearly all
of the capabilities of the interactive version. Voyager
is a command line tool that takes as arguments a camera position file,
a graphics operations file, and a list of
HDF files to process.
The camera postion and graphics operations files are generated during
an interactive session of Rocketeer using a representative
MPI to pass
messages. Once each processor knows which files to process, the camera
position, what graphics operations to perform, and the ranges of the
data for the color scales, it can generate each individual image and
save it to disk without additional communication. If the files reside
on local disk, Voyager is scalable to large numbers of
processors. Even if the files reside on a shared file system,
Voyager scales well until contention for I/O bandwidth
becomes significant. On subsequent runs with the same data (but
possibly different camera positions, isosurface values, etc.)
Voyager scales well if much of the data have been saved
by the system in local disk caches.
Like Rocketeer, Voyager works with
XFree86. However, for use on a large
cluster, CSAR contracted with
Xi Graphics to develop a commercial
quality X server with a virtual frame buffer that installs
automatically on all nodes without regard to the graphics hardware or
requiring administrator intervention.
Voyager is available on the
Turing cluster at
Man page on how to use Voyager.
Massively Parallel Visualization on Linux
Clusters with Rocketeer Voyager, presented at
Linux Clusters: the HPC Revolution on June 26, 2001 at NCSA.