[Users] Grid structure

Erik Schnetter schnetter at cct.lsu.edu
Fri Feb 8 07:42:36 CST 2013


Matt

(You are presumably speaking of the grid structure stored in HDF5 output
files, including in checkpoint files.) What do you intend to do with the
grid structure you so obtain?

If you are interested in the exact grid structure, then yes, this is the
correct way to do so. For example, when Carpet reads a grid structure e.g.
for recovery, it uses this information.

However, if you e.g. want to visualise data, then there is an alternative.
Each dataset (HDF5 component) contains attributes describing the coordinate
of its upper left corner as well as the coordinate distance between grid
points (grid spacing). This should suffice to correctly combine the
datasets you read in, and may be much simpler than parsing the grid
structure.

Note that the VisIt visualisation toolkit knows how to read Carpet output.
You could look at its reader for details.

If you are really interested in parsing the grid structure, then it may be
easier to discuss this in person. Are you available on Monday morning 11:00
EST for the Einstein Toolkit telecon? I can explain things there.

-erik



On Fri, Feb 8, 2013 at 8:15 AM, Matthew Turk <matthewturk at gmail.com> wrote:

> Hi all,
>
> I was wondering if someone could point me at how to parse the grid
> structure information in a Cactus output.  I hope this is the right
> venue for this type of question.
>
> In the output I'm examining, under the "Parameters and Global
> Attributes" node at root level, there's a "Grid Structure v5" dataset,
> which contains "grid_superstructure" and "grid_structure".  Is parsing
> the string affiliated with the grid_superstructure component the best
> way of identifying the spatial extent, dimensions and refinement level
> of grids in the output?
>
> Thanks very much for any pointers,
>
> Matt
> _______________________________________________
> Users mailing list
> Users at einsteintoolkit.org
> http://lists.einsteintoolkit.org/mailman/listinfo/users
>



-- 
Erik Schnetter <schnetter at cct.lsu.edu>
http://www.perimeterinstitute.ca/personal/eschnetter/
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