View source for Visualization recipes

=Horizons=

==QuasiLocalMeasures==
If one activates QuasiLocalMeasures, you can get each surface (which doesn't need to be an AH) output as VTK polygonal data, along with the various quantities that the thorn calculates, defined as fields on the surface. These can be then read by, e.g., VisIt. No postprocessing needed.

(Eloisa Bentivegna, http://lists.einsteintoolkit.org/pipermail/users/2015-October/004582.html)

==AHFinderdirect==
The thorn AHFinderdirect contains a script AH2xdmf.py (installed as utility in exe/CONFIGNAME/AH2xdmf.py, but can also be found as arrangements/EinsteinAnalysis/AHFinderDirect/src/util/AH2xdmf.py), which will search for AHFinderDirect horizon shape output files (ascii) in the current directory, and combine these into one HDF5 file per horizon (a time series). You can give it as command line argument a CarpetIOHDF5 output file (e.g., one of the regular 3D output file you want to visualize alongside), and instead of including in the horizon HDF5 file all timesteps when a horizon was found, it will only include timesteps for which there is also output in the regular output. This makes it easier to create movies in, e.g., visit - because it aligns the times automatically when you load the files.

Note: The script actually generates two files per horizon: an HDF5 file with the raw horizon data, and an .xml file with the meta-data (time steps, 6-patch system). Load the .xml file in visit, using the xdmf reader.

<pre>
$ AH2xdmf.py --help
Usage: AH2xdmf.py [filename]
Collect information about apparent horizon shape files within the current
directory and store them in hdf5 files. This assumes that the filename
scheme in AHFinderDirect (for ASCII output) has not been changed from the
default one.

The optional argument [filename] specifies another hdf5 file from which
timestep information will be read and used to create (if necessary dummy)
horizons for all timesteps in that file also in the apparent horizon output
files. The intend here is to allow visualization tools (like VisIt) to
automatically combine time sliders opon opening the specified file and the
created apparent horizon files.

The output files will be named AH_%d.[h5,xml], with %d being the number of each
horizon. The .h5 files contain the raw shape information, while the .xml files
describe its layout (and should be the one to open in a visualization tool).
</pre>