The dvrp
software developed by the RRZN
(Stephan Olbrich, Carsten Chmielewski) allows a creation of plot
sequences with PALM,
which can be animated via a special plugin for internet browsers. With
suitable graphic hardware even stereoscopic views are
possible.
In contrast to the other kinds of visualization output realized
in PALM (profil, iso2d and AVS),
where the data
is output in a format suitable for the plot software, the creation of
plots via dvrp
software is
integrated in PALM, i.e. respective routines are directly called within
the PALM code. The
dvrp
routines then output the
graphic data
(so-called plot-primitives, e.g. polygones of isosurfaces) in a special
dvr format. Since the dvrp
software is parallelized (i.e. each PE calculates the graphic data for
its subdomain), the visualization of simulations with very
large numbers of grid points is possible (which so far failed because
of
several problems: volume of the raw data, which rapidly may sum-up to
several Terabytes; main memory size needed for graphic workstations, on
which the visualization is to be carried out; the insufficient scalar
(!)
computing speed of commercial graphic software in case of such
large numbers of grid points).
The coupling of dvrp software and
PALM
as well as the visualization of the model results via dvrp has been
the main focus of the BMBF project "Application of
tele-immersion in long-distance networks" (2001-2002),
which was a joint project of RRZN, ZIB and IMUK. This work is currently
continued by RRZN in the new DFG-funded project "EVITA - Untersuchung
effizienter
Methoden zur visuellen und haptischen tele-immersiven
Exploration
komplexer Volumen- und Strömungsdaten aus
parallelisierten,
dynamischen 3D-Simulationen" (2005-2007).
The calls of the dvrp routines are contained within a PALM software package (see chapter 3.7). To use this package, the additional option -p “dvrp_graphics” has to be given in the mrun call. This automatically links the required libraries. Steering of the plot output is done via the package parameters (see chapter 4.2). In contrast to all other PALM output, dvrp graphic data are not output to local files but directly to a special remote computer which is defined via the package parameter dvrp_host. The default values of the dvrp parameters are cause the output to be directed to a so-called streaming server at the RRZN. Apart from graphic data an additional html file is created, which can be used by an internet browser to view the data (a special dvrp plugin is needed).
Since July 2001, the basic
functionality
of the dvrp
software is
installed in PALM and steerable via the
package parameters. However, some code modifications may still need to
be done by the user (e.g. in
the subroutine plot_dvrp
in order to define suitable color tables).
For further detailed information please ask Siegfried Raasch.
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