[MOAB-dev] VTK structured mesh outpu

[Grindeanu, Iulian R.]

Hello Paul,
I am not sure I understand what dagmc needs
(I should probably read the code in moab :)

Moab SCD interface is aligned with VTK structured grid  (legacy format, we do not do anything with XML)
( DATASET STRUCTURED_GRID)

in that, all points' coordinates are explicit, and in a specific order ( I think c style, need to check; need to check if it is the same convention in vtk)
all cells are "implicit", their connectivity is never stored, it is just derived from the dimensions (2d or 3d)

Moab's SCD interface allows all kinds of access. You can request neighbors, etc, and it works in parallel too, in the sense that each task has a very specific partition , it knows about neighbors, can do ghosting, etc. Pretty cool stuff, but rather verbose. Not sure if you need anything for parallel

An SCDBox from moab will correspond to a DATASET STRUCTURED_GRID from vtk

vtk has other "structured" meshes dataset types, that are simpler: STRUCTURED_POINTS and RECTILINEAR_GRID

Which one of those 3 does dagmc need?

Iulian

http://www.vtk.org/Wiki/VTK/Writing_VTK_files_using_python
http://www.vtk.org/wp-content/uploads/2015/04/file-formats.pdf




________________________________________
From: Paul Wilson [paul.wilson at wisc.edu]
Sent: Monday, September 19, 2016 4:13 PM
To: Grindeanu, Iulian R.; moab-dev at mcs.anl.gov
Subject: Re: [MOAB-dev] VTK structured mesh outpu

Hi Iulian,

We are much more interested in the writer, but might be convinced to
support a reader as well :)

We would want to explore the SCD interface to see how it could best
support this.

Our use case begins with MCNP mesh tally output files that are always
structured mesh.  There is a native reader in MOAB for these files, but
not as rich/robust as we'd like, and it does NOT use the scd interface,
instead making an unstructured representation.  There is also a reader
in the PyNE toolkit that does ultimately use the scd interface, but then
also relies on MOAB's vtk writer which stores an unstructured
representation.

The key to a structured (Cartesian) mesh VTK writer is having access to
the x,y,z bounds without having to infer them from the set of vertices.

The rest is probably straightforward.

Paul


On 09/19/2016 03:22 PM, Grindeanu, Iulian R. wrote:
> MOAB does not have a structured writer. Not even for h5m format
> (it has the ability to create structured meshes)
> even in that case, the mesh is written explicit (unstructured)
>
> structured vtk format is relatively simpler, but do you plan to add reader and writer or just writer?
>
> How do you create structured mesh, with scd interface?
>
> thanks,
> Iulian
> ________________________________________
> From: moab-dev-bounces at mcs.anl.gov [moab-dev-bounces at mcs.anl.gov] on behalf of Paul Wilson [paul.wilson at wisc.edu]
> Sent: Monday, September 19, 2016 3:12 PM
> To: moab-dev at mcs.anl.gov
> Subject: [MOAB-dev] VTK structured mesh outpu
>
> Hi all,
>
> Does the MOAB VTK writer have a way to write structured mesh data using
> VTK's structured mesh format?  For data that conforms to that, it saves
> a substantial amount of disk space and also speeds up
> processing/visualization times.
>
> If not, we may be interested in helping add this...
>
> Paul
>
>
> --
> -- ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ --
>
> Paul P.H. Wilson
> Grainger Professor of Nuclear Engineering
> 608-263-0807
> paul.wilson at wisc.edu
> 419 Engineering Research Bldg
> 1500 Engineering Dr, Madison, WI 53706
> calendar: http://go.wisc.edu/pphw-cal
>
> Computational Nuclear Engineering Research Group
> cnerg.engr.wisc.edu
>
> Faculty Director, Advanced Computing Initiative
> aci.wisc.edu
>

--
-- ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ --

Paul P.H. Wilson
Grainger Professor of Nuclear Engineering
608-263-0807
paul.wilson at wisc.edu
419 Engineering Research Bldg
1500 Engineering Dr, Madison, WI 53706
calendar: http://go.wisc.edu/pphw-cal

Computational Nuclear Engineering Research Group
cnerg.engr.wisc.edu

Faculty Director, Advanced Computing Initiative
aci.wisc.edu