Hello,

I need to solve the linear problem shown in the screenshot:

where `phi`

is a scalar function, whereas `f`

is expressed in terms of a vector function `m`

:

```
phi = fem.Function(fem.FunctionSpace(domain,("CG", 1)))
m = fem.Function(fem.VectorFunctionSpace(domain, ("CG", 1), dim=domain.topology.dim))
```

I have a mesh which consists of 2 cubes, one inside the other.

I need to solve the linear problem only on the inside domain `\Omega_m`

.

Following the example you provided here Solve a problem of parts of a unit square mesh · GitHub

I defined 2 sub-meshes and I am trying to solve the problem on one of the two.

For that, I’d like to transfer the data of the vector field `m`

from the parent mesh to the submesh.

Unfortunately, I don’t know how to adapt the function `transfer_submesh_data`

from your tutorial to a CG1 vector field.

Could you please help?

Thank you