Probe.py can be used to read out the unknowns at a given point within a Peano patch file.

That is, it identifies the unknowns that are associated with an individual cell that is specified through an x, y and (optional) z coordinate. Crucially, the single cell is found at the finest level of granularity recorded in the peano patch file.

The algorithm does not rely on Paraview/pvpython.

To probe an individual patch file use the following commands:

cd Peano export PYTHONPATH=python python3
python/peano4/visualisation/Probe.py
--input-file=\<path-to-peano-patch-file\> -x=\<x-axis\> -y=\<y-axix\>
--set-identifier=\<set-identifier\>

Here we probe the patch file passed to –input-file. The point to be probed is given as a coordinate to -x and -y. If you work with three dimensional data add a -z argument with the value of the z axis to be probed. The unkowns at the point (x, y) will be saved in a csv file called probe_output.csv, though the name of this file can be configured by adding the –ofname flag to the above command and setting it to the name of the output file.

We can also probe whole sets of patch files at once by swapping the –input-file flag used above with the –meta-file flag instead. The –meta-file should be set as the path to the main file that links to a set of Peano patch files. The algorithm will then probe all files that are listed in the main file.

In this case, each row in the outputted csv file will list the unknowns from an individual patch file. The rows are ordered chronologically. This csv, then, will capture the change in unknowns at a given point within the mesh over time.