[Dune] reading multiple tags with GmshReader

[Benedikt Oswald]

Dear Ganesh,

We have implemented a parallel gumsh reader that reads all the tags. Why not try this? Ask Aleksejs, you'll find his coordinates on the mailing list. Also, why not use our dune-curvilineargrid? It is parallel, reads gmsh files including higher order elements.
Over and out, Benedikt


dr. benedikt oswald - Suisse

Am 19.06.2015 um 07:40 schrieb Oliver Sander <sander at igpm.rwth-aachen.de>:

> Am 18.06.2015 um 20:56 schrieb Christian Engwer:
>> Dear Ganesh,
>> 
>> sadly in the current state none of this works. Oli recently removed
>> the half-implement reader for more than one tag, as it was never
>> finished. Reading other things than elements or boundary elements is
>> currently not possible.
>> 
>> In the issue you reference, nobody ever offered a patch and further
>> more the author never replied to my questions.
>> 
>> But perhaps you can answer some of them:
>> * Which information can be added as a tag. Is this restricted to int,
>>  or can it be arbitrary data, e.g. double values?
> 
> As I understand the spec, and element can have an arbitrary positive number of
> integer tags.
> 
>> * Is it only possible to use additional tags for cells, or also for
>>  boundary entries? Reading your comment below I guess there is also
>>  some way to add tags to other entities!?
> 
> Yes, that is possible.  The boundarySegmentToPhysicalEntity field actually
> returns the first tag of each codim-1 entity.
> 
>> 
>> and which program can I use to generate such files? My Gmsh
>> installation only uses the physical entity tag.
>> 
>> If you are interested in providing patches, I'll happily guide you
>> through the code to implement the missing features. Reagrding the
>> cells should be fairly simple once we know what type of data can be
>> attached. We basically have to revert Olis recent patch and add an
>> additional constructor which takes more than one vector.
> 
> Maybe we can think a little before adding a new constructor.  Just adding
> another vector argument still does not cover all the generality of the
> file format.
> 
>>> partition info tags as well. Additionally, is there a way to extract the
>>> tags (physical, geometry and partition) for the edge-element (denoted by a
>>> type 1 element in Gmsh, eg. a 2-noded edge of a 4-noded quadrilateral) as
>>> well?
> 
> The 'physical' for edge elements are returned in the boundarySegmentToPhysicalEntity
> field.
> 
> --
> Oliver
> 
>>> 
>>> I see that this issue was considered before (FS#935) but I do not know if
>>> it was resolved and a patch was applied.
>>> 
>>> 
>>> Ganesh
>> 
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> 
> 
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