Comment (by William Gabella):

Running VisIt you can restore the attached session files. Here the 8 files u.file_N.h5 with N=0…7 are the 3D “database” files of format CarpetHPDF5. However if you did not run with 8 MPI tasks (?) or have a different file structure than this run, you will have to create the plot with VisIt manually. The following should get you pretty close:

singularity run docker://symerio/visit  

And is currently version 2.12.3 .  You can restore the *.session file, or if your file structure is different do the following "by hand."
o Start VisIT;
o Sources Open file name like u.file.* as database and select manually CarpetHDF5 --

Ticket URL: https://bitbucket.org/einsteintoolkit/tickets/issues/2174/test-multi-patch-scalar-wave-equation