Hi Peter,
Thanks a lot for the suggestion. With it I think I managed to achieved the
desired effect. First, I populated a
LinearAlgebra::distributed::Vector with the material ids and called
the update_ghost_values() method afterwards. In a second
active_cell_iterator I used said vector and the global_active_cell_index()
of each cell pair for the boolean comparison of the material id. I could
not do a visual verification due to the assertion data_vector.size() ==
triangulation->n_active_cells() inside the add_data_vector() method with
DataVectorType::type_cell_data as third argument, i.e.,
data_out.add_data_vector(
cell_is_at_interface,
"cell_is_at_interface",
dealii::DataOut_DoFData, dim,
dim>::DataVectorType::type_cell_data);
The assertion does not hold for a distributed vector as
n_global_active_cells > n_active_cells. Maybe this is not the correct
method for LinearAlgebra::distributed::Vector? Nevertheless, I
instead counted the amount of times the boolean comparison was true and it
coincides with what it is expected from the amount of global refinements of
the unit square (with 3 global refinements there are a total of 16 cells at
the interface) and I checked the x-coordinate of the cells' center to
verify that it is indeed at the interface.
It seems that when working in parallel out of the methods
CellAccessor::material_id(), CellAccessor::active_fe_index() and
CellAccessor::global_active_cell_index(), only the latter returns the
correct value when called from a neighbor cell outside the locally owned
subdomain. I could observe this when printing the global_active_cell_index,
active_fe_index and the material_id pairs each the the boolean comparison
was true. Here are the results in serial
Global active cell index pair ( 5, 16) with active_fe_index pair ( 1,
2) and material_id pair ( 1, 2)
Global active cell index pair ( 7, 18) with active_fe_index pair ( 1,
2) and material_id pair ( 1, 2)
Global active cell index pair (13, 24) with active_fe_index pair ( 1,
2) and material_id pair ( 1, 2)
Global active cell index pair (15, 26) with active_fe_index pair ( 1,
2) and material_id pair ( 1, 2)
Global active cell index pair (16, 5) with active_fe_index pair ( 2,
1) and material_id pair ( 2, 1)
Global active cell index pair (18, 7) with active_fe_index pair ( 2,
1) and material_id pair ( 2, 1)
Global active cell index pair (24, 13) with active_fe_index pair ( 2,
1) and material_id pair ( 2, 1)
Global active cell index pair (26, 15) with active_fe_index pair ( 2,
1) and material_id pair ( 2, 1)
Global active cell index pair (37, 48) with active_fe_index pair ( 1,
2) and material_id pair ( 1, 2)
Global active cell index pair (39, 50) with active_fe_index pair ( 1,
2) and material_id pair ( 1, 2)
Global active cell index pair (45, 56) with active_fe_index pair ( 1,
2) and material_id pair ( 1, 2)
Global active cell index pair (47, 58) with active_fe_index pair ( 1,
2) and material_id pair ( 1, 2)
Global active cell index pair (48, 37) with active_fe_index pair ( 2,
1) and material_id pair ( 2, 1)
Global active cell index pair (50, 39) with active_fe_index pair ( 2,
1) and material_id pair ( 2, 1)
Global active cell index pair (56, 45) with active_fe_index pair ( 2,
1) and material_id pair ( 2, 1)
Global active cell index pair (58, 47) with active_fe_index pair ( 2,
1) and material_id pair ( 2, 1)
and in parallel (-np 3)
Global active cell index pair (24, 13) with active_fe_index pair ( 2,
0) and material_id pair ( 2, 0)
Global active cell index pair (26, 15) with active_fe_index pair ( 2,
0) and material_id pair ( 2, 0)
Global active cell index pair (37, 48) with active_fe_index pair ( 1,
0) and material_id pair ( 1, 0)
Global active cell index pair (45, 56) with active_fe_index pair ( 1,
2) and material_id pair ( 1, 2)
Global active cell index pair (47, 58) with active_fe_index pair ( 1,
2) and material_id pair ( 1, 2)
Global active cell index pair (48, 37) with active_fe_index pair ( 2,
0) and material_id pair ( 2, 0)
Global active cell index pair (50, 39) with active_fe_index pair ( 2,
0) and material_id pair ( 2, 0)
Global active cell index pair (56, 45) with active_fe_index pair ( 2,
1) and material_id pair ( 2, 1)
Global active cell index pair (58, 47) with active_fe_index pair ( 2,
1) and material_id pair ( 2, 1)
Global active cell index pair ( 5, 16) with active_fe_index pair ( 1,
2) and material_id pair ( 1, 2)
Global active cell index pair ( 7, 18) with active_fe_index pair ( 1,
2) and material_id pair ( 1, 2)
Global active cell index pair (13, 24) with active_fe_index pair ( 1,
0) and material_id pair ( 1, 0)
Global active cell index pair (15, 26) with active_fe_index pair ( 1,
0) and material_id pair ( 1, 0)
Global active cell index pair (16, 5) with
