[Dune] Reading arbitrary polygonal meshes in Dune

[Benedikt Oswald]

aha. But still, what about triangulating into triangles and assigning a
certain tag to a group of elements
that form the original polygon, then evaluating the algorthm based on
triangles with that same tag ? Benedikt

Am 26/02/15 um 15:01 schrieb Christian Engwer:
> Hi Benedikt,
>
> he says he wants to use the virtual element method and there the main
> idea is to have a method which wokrs on arbitrary polygons.
>
> Christian
>
> On Thu, Feb 26, 2015 at 02:56:01PM +0100, Benedikt Oswald wrote:
>> Hello Ganesh
>>
>> a simpler, relatively straighforward approach could be
>> to read your polygons into gmsh and then have gmsh
>> triangulate them, into triangles. The same approach
>> would also work in 3D. Then, there is not need to
>> write a new grid. Greetings, Benedikt
>>
>> Am 26/02/15 um 14:49 schrieb Christian Engwer:
>>> Hi,
>>>
>>> currently no grid can handle such elements. Once upon a time there was
>>> a simple implementation, which was able to handle arbitrary polygonal
>>> elements in 2D with out refinement. But this doesn't work with the
>>> current Dune anymore. On the other hand I believe it wouldn't be too
>>> difficult to implement such a mesh, as we have introducent several
>>> changes in the interface to allow for non-standard meshes (this was
>>> all with the cornerpoint mesh in mind).
>>>
>>> Ciao
>>> Christian
>>>
>>> On Thu, Feb 26, 2015 at 12:02:02PM +0000, Andreas Dedner wrote:
>>>> Hi.
>>>> The main problem is not the grid type or the factory but that you
>>>> need an actual
>>>> grid implementation that can handle these general meshes. ALU and
>>>> SPGrid etc.
>>>> can only handle cubes and simplex elements and that is the only
>>>> geometry types
>>>> they can understand in their GridFactory.
>>>>
>>>> So for something more general you need to provide a new grid
>>>> implementation that
>>>> allows for more general grid types. The geometry type of these
>>>> elements would be
>>>> "none" and probably you would also be implementing only part of the
>>>> geometry interface.
>>>> Something along those lines was done in the CornerPointGrid implementation.
>>>> https://github.com/OPM/dune-cornerpoint
>>>>
>>>> Best
>>>> Andreas
>>>>
>>>>
>>>>
>>>> On 26/02/15 11:38, Ganesh Diwan wrote:
>>>>> Dear list,
>>>>>
>>>>> I am working on implementing virtual element computations inside
>>>>> Dune. This will involve implementing the algorithm on arbitrary
>>>>> shaped elements. Is there a way to read arbitrary polygonal (2d)
>>>>> or polyhedral (3d) meshes in Dune? Currently implemented Grid
>>>>> managers (ALUGrid, SPGrid etc.) identify either simplices or cube
>>>>> types.
>>>>>
>>>>> Can the GridFactory class be used for this purpose? Grid-howto
>>>>> document says when building a new gridtype Dune may have a problem
>>>>> for unidentified element type. Say, I have an element with five
>>>>> edges (a pentagon). In this case, is Dune likely to throw an
>>>>> exception for unidentified element type?
>>>>>
>>>>> I wanted to get the Grid guru's thoughts before investing time in this.
>>>>>
>>>>> Thank you!
>>>>> Ganesh
>>>>>
>>>>>
>>>>> _______________________________________________
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>> -- 
>> ------------------------------------------------------------------------------------------------
>> Dr. sc. techn. Benedikt Oswald - first engineer - LSPR AG - phone - +41 43 366 90 74
>> Technoparkstrasse 1, CH-8005 Zürich, benedikt.oswald at lspr.ch - labor vincit omnia improbus
>> ------------------------------------------------------------------------------------------------
>>
>>
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-- 
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Dr. sc. techn. Benedikt Oswald - first engineer - LSPR AG - phone - +41 43 366 90 74
Technoparkstrasse 1, CH-8005 Zürich, benedikt.oswald at lspr.ch - labor vincit omnia improbus
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