[Dune] Gmsh reader crashes when using the grid factory read for ALUSimpleGRid<3, 3> with boundary id
Andreas Dedner
dedner at mathematik.uni-freiburg.de
Wed Oct 14 12:23:19 CEST 2009
So how does Benedict attach his boundary IDs found in the gmsh file
to an UG grid?
Oliver Sander wrote:
> Hi Andreas!
> Peter, Christian, Benedikt and I put forth a proposal on how boundary
> ids should be
> handled by the GridFactory. It is described in the grid howto, even
> though we are
> fully aware that it is not yet part of the interface and needs a formal
> vote first.
> UG implements that proposal.
>
> --
> Oliver
>
> Andreas Dedner schrieb:
>> There are two method for doing something at the boundaries:
>> 1) the one in the interface with the default implementation;
>> this method is used in UG and does not have the possibility to
>> set boundary ids as far as I know
>> 2) the method
>> virtual void
>> insertBoundary ( const GeometryType &geometry,
>> const std::vector< unsigned int > &faceVertices,
>> const int id );
>> used in the ALU factory which supports boundary ids.
>>
>> So the ALUGridFactory has the method you need - I did a search for this
>> in the gmeshreader and could not find anything. So prehaps Peter can
>> comment on how IDs can be handled through the gmsh reader?
>> Andreas
>>
>> Oswald Benedikt wrote:
>>
>>> Hi Again, thanks for the feeback!
>>>
>>> Yes, we definitely need boundary id's, since boundary conditions in
>>> electromagnetics are very critical
>>> (as they certainly are in other fields of physics as well) and may
>>> vary over the boundary considerably.
>>>
>>> For example, we will very soon have a postdoc here who will even need
>>> fictitious boundaries, i.e. internal boundaries
>>> that are used for evaluating electric and magnetic currents that are
>>> then used for evaluating Green's
>>> functions on the real boundary, the subject is discontinuous Galerkin
>>> methods combined with
>>> boundary integrals in order to achieve an accurate absorbing boundary
>>> conditions that can be
>>> placed very close to radiating structures, the application is in
>>> nano-optics.
>>>
>>> I do not know how to do this in DUNE at the moment, but I think other
>>> fields may need this as well.
>>>
>>> BUT, at the moment, boundary id's on the outside boundary would
>>> already be very useful.
>>>
>>> As far as I can see from the gmshreader docu, it does support
>>> boundary id's.
>>> Peter Implented them in July or so.
>>>
>>> Therefore, if you could reconsider implementing them, this would be
>>> appreciated very much!
>>>
>>> Have a great day, Benedikt
>>>
>>>
>>> ------------------------------------------------------------------------------------------------------------------
>>>
>>> Benedikt Oswald, Dr. sc. techn., dipl. El. Ing. ETH, www.psi.ch,
>>> Computational Accelerator Scientist
>>> Paul Scherrer Institute (PSI), CH-5232 Villigen, Suisse,
>>> benedikt.oswald at psi.ch, +41(0)56 310 32 12
>>> "Passion is required for any great work, and for the Revolution
>>> passion and audacity are required in big doses.", Ernesto 'Che'
>>> Guevara, Letter to his parents.
>>> http://maxwell.psi.ch/amaswiki/index.php/User:BenediktOswald
>>> ------------------------------------------------------------------------------------------------------------------
>>>
>>>
>>>
>>>
>>>
>>> -----Original Message-----
>>> From: Andreas Dedner [mailto:dedner at mathematik.uni-freiburg.de]
>>> Sent: Wed 14.10.2009 11:42
>>> To: Oswald Benedikt
>>> Cc: dune at dune-project.org
>>> Subject: Re: [Dune] Gmsh reader crashes when using the grid factory
>>> read for ALUSimpleGRid<3, 3> with boundary id
>>>
>>> Hi,
>>>
>>> I agree that gmsh support for ALU would be nice - but it is not so
>>> much an ALU problem as a gmsh reader problem IMO.
>>> Thus I would say that the flyspray task was not critical bug in ALU
>>> but more a feature request for the gmsh reader :-) But since the
>>> boundary
>>> insertion method are not standard this might be difficult to add
>>> to the gmsh reader at the moment.
>>>
>>> The problem with the misleading documentation is in
>>> fact that the method is available on the interface class with a default
>>> implementation (a DUNE_THROW). The method is then not overloaded in
>>> the alugrid factory and thus not only inherits the method but also
>>> its documentation. As I already said, the interface methods for
>>> inserting boundaries has not been fixed yet.
>>>
>>> Do you actually need boundary ids? If so I think the gmsh reader does
>>> not support these (as far as I know).
>>>
>>> Best Andreas
>>>
>>>
>>> Oswald Benedikt wrote:
>>>
>>>> Hi ALU Developers, I am mildly suprised about your comments.
>>>>
>>>> Wouldn't it be good to provide different methods for mesh input into
>>>> ALUGrid quite soon,
>>>> particularly when there is a need from users ?
>>>>
>>>> This is not about deprecating DGF, by the way, be assured!
>>>>
>>>> I might add that, here, we use probably dozens of grids that we
>>>> created in GMSH
>>>> and then, with some effort, convert into the DGF format, which we
>>>> still plan rto use intensively.
>>>>
>>>> Anyway, the documentation of Dune::GridFactory< ALUSimplexGrid< 3, 3
>>>> > > Class Template Reference
>>>> (http://www.dune-project.org/doc/doxygen/dune-grid-html/classDune_1_1GridFactory_3_01ALUSimplexGrid_3_013_00_013_01_4_01_4.html#_details)
>>>>
>>>> says that the method virtual void
>>>>
>>>> "insertBoundarySegment (const std::vector< unsigned int > vertices,
>>>> const BoundarySegment< dimension, dimworld > *boundarySegment)
>>>> Method to insert an arbitrarily shaped boundary segment into a
>>>> coarse grid. "
>>>>
>>>> is here.
>>>> That is the source of my quite convinced feeling that it should be
>>>> available.
>>>>
>>>>
>>>> More, or even most, importantly, reading large meshes from the DGF
>>>> format, may not be ultra-fast after all.
>>>>
>>>> When I say large, I mean 10^5 or more tetrahedral elements. This is
>>>> the size of the meshes that we have to cope
>>>> with here when running electromagnetic simulations and I think for
>>>> ALUGrid to be relevant in the future
>>>> it must address users's needs.
>>>>
>>>> After all, I have always believed that DUNE and its external
>>>> libraries are
>>>> a great achievement, meant to be capable of solving today's and
>>>> tomorrow's large problems.
>>>>
>>>>
>>>> Have a great day! Benedikt
>>>>
>>>>
>>>>
>>>>
>>>>
>>>>
>>>>
>>>>
>>>>
>>>>
>>>>
>>>>
>>>>> S#624 - [Dune] Gmsh reader crashes when using the grid factory read
>>>>> for ALUSimpleGRid<3, 3> with boundary id
>>>>> User who did this - Robert Klöfkorn (robertk)
>>>>> ----------
>>>>> This feature is not supported yet. I don't know you got the feeling
>>>>> that it is implemented. There will be an anouncement on the mailing
>>>>> list when the gmsh boundary ids are supported. Until then: DON'T
>>>>> USE IT !!!
>>>>
>>>> ------------------------------------------------------------------------------------------------------------------
>>>>
>>>> Benedikt Oswald, Dr. sc. techn., dipl. El. Ing. ETH, www.psi.ch,
>>>> Computational Accelerator Scientist
>>>> Paul Scherrer Institute (PSI), CH-5232 Villigen, Suisse,
>>>> benedikt.oswald at psi.ch, +41(0)56 310 32 12
>>>> "Passion is required for any great work, and for the Revolution
>>>> passion and audacity are required in big doses.", Ernesto 'Che'
>>>> Guevara, Letter to his parents.
>>>> http://maxwell.psi.ch/amaswiki/index.php/User:BenediktOswald
>>>> ------------------------------------------------------------------------------------------------------------------
>>>>
>>>>
>>>>
>>>>
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>>
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