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Mixed spaces Bilinearform

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3 years 5 months ago #3361 by paul.stocker
Mixed spaces Bilinearform was created by paul.stocker
Hi everyone!

I was wondering how to create a BilinearForm with test and trial functions from different spaces.
In the code the MixedSpaces() option for the BilinearForm is marked as non operational and also implementation for skeleton terms is missing. Would the rest work? Is there any sense in extending the code or is there a work around using product spaces?

Cheers,
Paul
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3 years 5 months ago #3363 by schruste
Replied by schruste on topic Mixed spaces Bilinearform
Hi Paul,

mixed spaces for the BilinearForm are functional. Even skeleton forms (at least for interior facets) are working. I guess only skeleton boundary forms and element_boundary forms that access neighboring elements are not implemented at the moment. A very simple (but not meaningful) example of what is working is here:
Code:
V1 = L2(mesh, dgjumps=True) V2 = L2(mesh, order=2, dgjumps=True) u = V1.TrialFunction() v = V2.TestFunction() a = BilinearForm(trialspace=V1,testspace=V2) a+= (u-u.Other())*(v-v.Other())*dx(skeleton=True) a.Assemble()

Best,
Christoph
The following user(s) said Thank You: paul.stocker
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3 years 5 months ago #3365 by paul.stocker
Replied by paul.stocker on topic Mixed spaces Bilinearform
Hi Christoph,
thanks!! I would need the skeleton boundary forms, I will see if I can get them working!
Best,
Paul
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3 years 5 months ago #3366 by schruste
Replied by schruste on topic Mixed spaces Bilinearform
Hi Paul,

I see. It shouldn't be a big deal if you take a look at the non-mixed-space implementation of skeleton boundary forms. There shouldn't be any severe obstacle. It is just not implemented yet as it wasn't needed so far.
If you succeeded with your own implementation, please make a merge/pull request on github. If you have problems, let us know. I am willing to take a closer look myself if problems occur.

Best,
Christoph
The following user(s) said Thank You: paul.stocker
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3 years 5 months ago #3369 by paul.stocker
Replied by paul.stocker on topic Mixed spaces Bilinearform
Hi Christoph,
amazing, thanks again! I think I got it working, I will do a few more tests and then make a pull request.
Best, Paul
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3 years 4 months ago #3409 by paul.stocker
Replied by paul.stocker on topic Mixed spaces Bilinearform
Hi Christoph,
I have now submitted the pull request on github!
Cheers,
Paul
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