Error: Expected a Function or linear combinations of Functions in the same FunctionSpace

1

I am working on time dependent problem with mixed space H = (RT1, CG1)
w = Function(H), w = function(t)
(q, u) = split(w)
w is obtained from the system AW = B.
I have to update (q,u) with each time step, but while assignment it gives me error as

``Expected a Function or linear combinations of Functions in the same FunctionSpace’’

The end part of my code in while loop reads
Thanks !!



solve(A == B, W)
q = W.split(0)
u = W.split(1)
u0.assign(u)
q0.assign(q)
2

You need supply a minimal working code example.
Note that you should check the forum for similar posts before creating a new post, see for instance:

3

I think I tried it but was not working. But I shall check again.

4

As you have not supplied a minimal working code example, this is the only guidance I can Give you.
Please provide an example that can reproduce the error. Note that you do not Need to define a PDE in the minimal example, as it is only related to assign. So please define your mesh, FunctionSpace and relevant functions, and try to assign one to the other.

5

Thank you so much.
I shall first try to work out the through the post which you just shared.
Because of short time I generally skip writing the code.
Is there any documentation where these codes exist. I am a beginner in fenics and making first code …have been following
Lecture notes: Automated Solutions … Anders Logg . et al.
But I find things are quite different.

6

As this book was published in 2012, the software has changed quite a lot since then. If you base your work around the 2016.2.0 version, you can use:

7

Thanks you very much Dokken !!