Dear All,
I'm trying to implement the P1ISOP2 element for the Stokes problem on a square.
To do this I need to work with two different mesh, in particular, I need the test function to be on coarser mesh than the trial function.
I generate both meshes using the MakeStructured2DMesh function with the Quad flag set to False.
Now when I try to build this the bilinear form B = div(u)*q*dx I get the error that both trial and test space must be defined on the same space.
Do you have any suggestions on how to proceed?
In my mind, a solution could have been to create a custom mixed finite element integrator, as shown in
github.com/NGSolve/mylittlengsolve
but I it seems I'm not able to build mylittlengsolve.
Thank you very much for your help!
Kind Regards,
Umberto Zerbinati