On Mon, Dec 1, 2025 at 8:22 AM Aldo Bonfiglioli <aldo.bonfiglioli@unibas.it> wrote:
Dear developers,

I wrote a code that extracts subDMs corresponding to the various strata
in the Face Sets.

I run into troubles when I view a subDM or a Vec attached to the subDM
using the VTK format.

More precisely, the problem only occurs on more than one processor when
the rank=0 processor has no points on a given subDM.

For instance, when the attached reproducer is run on 2 procs, the
u_01.vtu file (global u Vec mapped to the subDM corresponding to stratum=1)

only includes the header, but no data. All other u_0?.vtu files can
successfully be loaded and viewed in paraview.

The problem does NOT arise when I view the same objects in HDF5 format.

However, my problem in using the HDF5 lies in the fact that:

while the hdf5 file obtained with DMView can be post-processed with
"petsc/lib/petsc/bin/petsc_gen_xdmf.py" to create a xmf file readable by
paraview

Hi Aldo,

Sorry about this, I would like to make it more intuitive. First, the solution (I think)

  -dm_plex_view_hdf5_storage_version 1.1.0

will write the Viz field by default, so that PAraview will see it. Can you try this?

Why do we need this? I have now made version-controlled output formats. There is something about
this in the manual, but not enough. Paraview only supports vertex-based fields and cell-based fields
(at least that I understand), so we need to write a separate copy of the field (since Plex supports any
layout). Lots of people do not want a separate copy, since they are checkpointing, so we control this
with a format (PETSC_VIEWER_HDF5_VIZ). You can pass this for specific output, or use the format
version that does it automatically.

Let me know if this works.

  Thanks,

     Matt
 
I do not know how to view the field(s) associated with the DM when the
hdf5 file is obtained from VecView.

The reproducer compiles with the latest petsc release.

Thanks,

Aldo

--
Dr. Aldo Bonfiglioli
Associate professor of Fluid Mechanics
Dipartimento di Ingegneria
Universita' della Basilicata
V.le dell'Ateneo Lucano, 10 85100 Potenza ITALY
tel:+39.0971.205203 fax:+39.0971.205215
web: https://urldefense.us/v3/__http://docenti.unibas.it/site/home/docente.html?m=002423__;!!G_uCfscf7eWS!eXE2csxUb1J5bnRosf9LIGxLs17TdstMxQcGs0mbXFroRjzLN81jVmeAWfMr41X8JGEuVm286lVTmDgmi5s1zfsfegJNuWVVWTM$


--
What most experimenters take for granted before they begin their experiments is infinitely more interesting than any results to which their experiments lead.
-- Norbert Wiener