Dear fellows,

I am using the vector valued function space with element degree >1 . When I calculate the solution u on one submesh e.g. half_cube_mesh, then I want to transfer it to my next mesh which is quarter_cube_mesh.

It should be in such a way that the half cube zone of quarter_cube_mesh should have the same solution assigned as available in the half_cube_mesh and rest (1/3 rd) of the zone’s solution being zero.

Does anyone have a very simple idea to do it in fenics? Thank you!

```
from dolfin import *
class HalfDomain(SubDomain):
def inside(self, x, on_boundary):
return between(x[0], (0, 0.5))
class QuarterDomain(SubDomain):
def inside(self, x, on_boundary):
return between(x[0], (0, 0.75))
mesh_Complete = UnitCubeMesh(8,8,8);
mark_sub_domain = MeshFunction("size_t", mesh_Complete, mesh_Complete.topology().dim(), 0)
mark_sub_domain.set_all(0)
mark_domain = HalfDomain()
mark_domain.mark(mark_sub_domain, 1)
half_cube_mesh = SubMesh(mesh_Complete, mark_sub_domain, 1)
mark_sub_domain.set_all(0)
mark_domain = QuarterDomain()
mark_domain.mark(mark_sub_domain, 1)
quarter_cube_mesh = SubMesh(mesh_Complete, mark_sub_domain, 1)
V_half_cube = VectorFunctionSpace(half_cube_mesh, "Lagrange", 2)
u_half_cube = Function(V_half_cube, name="u_half")
##############################################################################
# here solver performs the solution on the half cube and returns the solution vector u_half_cube #
##############################################################################
V_quarter_cube = VectorFunctionSpace(quarter_cube_mesh, "Lagrange", 2)
u_quarter_cube = Function(V_quarter_cube, name="u_quarter")
########################################################
# now the u_half_cube has to be transferred to the u_quarter_cube #
# before starting the solver for quarter_cube_mesh #
#########################################################
```