Add Real Space

[jhale]

Builds on previous work of @mscroggs.

Currently brings in tensor related branches from @garth-wells so would need to wait before merging.

[michalhabera]

What is the parallel ownership of real element dofs?

For performance reasons we could pack coefficients of Real element in a similar way to how Constants are packed - outside of the main assembly loop, just once per domain. Legacy approach to Real element has many bottlenecks, I thought we opted for redesign.

[tbrandvik]

I have some old Dolfin-based code that makes use of real spaces that I am trying to port to DolfinX. I was wondering if the capability in this branch is likely to be merged with the main branch in the near future or if I am better off using this branch directly? Thanks!

[jhale]

Perhaps not @tbrandvik, because I agree with @michalhabera that there are better ways of doing this. I have a research problem that required this implementation and I had to get it done quickly (it worked for my purposes).

I would add that this branch does not currently work in parallel, and the inner product of a real function and a finite element function in a form is also not giving the right output. So be careful!

[tbrandvik]

Thanks @jhale - that is useful information. Hopefully support for real spaces become part of the main branch at some point!

[GSadashivaiah27]

Hi,

As I understand real space is still not available within DolfinX? or Is there a way to use it.

[twmr]

I'm also interested in this feature. BTW Are there plans when the tensor related branches by @garth-wells will be merged?

[ramrebol]

I'm also interested in this feature. Do you think it will be incorporated?

[garth-wells]

It will be added at some point (hopefully soon). I still needs some careful thought on how to do it while maintaining decent performance.

[ramrebol]

thanks @garth-wells for answer. May you suggest me a better way to impose the integral of the pressure equal to zero in a Stokes problem? (Typical stationary Stokes problem with Dirichlet boundary condition only).

[jkrokowski]

Any status updates on this issue? I have an application in which I would like to use real type spaces.

[garth-wells]

We need to come back to this with a focused effort. Closing for now.