[petsc-dev] DMPlex reader / viewers

[Tim Tautges (ANL)]

On 01/22/2014 11:29 AM, petsc-dev-request at mcs.anl.gov wrote:
> Message: 3 Date: Wed, 22 Jan 2014 17:26:02 +0000 From: Blaise A Bourdin<bourdin at lsu.edu> To: Jed
> Brown<jed at jedbrown.org> Cc: petsc-dev<petsc-dev at mcs.anl.gov> Subject: Re: [petsc-dev] DMplex reader / viewers
> Message-ID:<6A6423C9-5C9A-4C6E-92F8-29122FC2B8F9 at lsu.edu> Content-Type: text/plain; charset="Windows-1252"
>
>
> On Jan 22, 2014, at 10:57 AM, Jed Brown<jed at jedbrown.org>  wrote:
>
>>> Moving back to list.
> sorry, muscle memory prevents me from hitting that reply-to button
>
>>>
>>> Blaise A Bourdin<bourdin at lsu.edu>  writes:
>>>
>>>>> On Jan 21, 2014, at 11:20 AM, Jed Brown<jed at jedbrown.org>  wrote:
>>>>>
>>>>>>> Matthew Knepley<knepley at gmail.com>  writes:
>>>>>>>>> - Reading from or writing to exodus files is not supported.
>>>>>>>>>>>
>>>>>>>>>
>>>>>>>>> Yes, I think this is the best target. It should be similar to writing HDF5 that we do for PyLith.
>>>>>>>
>>>>>>> How are we going to represent high-order elements in Exodus?  Doesn't it only support quadratic
>>>>>>> continuous spaces?  What about DG spaces, H(div) spaces, or higher than second order?
>>>>>
>>>>> It only supports first and second order elements. I don?t think that continuity is an issue. Nothing prevents
>>>>> you to alter the connectivity table. Element types is set by blocks, so mixing polynomial orders is not
>>>>> possible without some trickery
>>>
>>> Do we consider this an acceptable long-term solution?
> hell no!
>
> Does anybody knows of any open and widespread format supporting elements of order >2? I checked quickly, and
> according to their documentation it seems that none of exodusii, silo 4.7, or xdmf support them...
>

MOAB supports this, with certain constraints (if one facet of an element is resolved with higher-order nodes, they all 
have to be), including I/O.  But, you'd have to modify any viz tool to handle those elements (e.g. both Paraview and 
Visit interpret Nek5000's Nth order spectral element as NxN linear elements.

- tim

> Incidentally, exodus docs last update is from 2006,silo?s from 2010, andhttp://www.xdmf.org  has seen minor edits
> after 2009... I seem to recall that the project is now hosted with visit. Not sure.
>
> Blaise

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              Tim Tautges            Argonne National Laboratory
          (tautges at mcs.anl.gov)      (telecommuting from UW-Madison)
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