Wrong vertices at the boundary

[Masoud Ahmadi]

Hi All,

I'm trying to get the vertices of faces at the boundary; however, something goes wrong.

For example, consider a simple mesh for a square of 4X4 as:

GridGenerator::hyper_cube(triangulation, -1, 1);

triangulation.refine_global(2);

Then, we say:

for (const auto &cell : dof_handler.active_cell_iterators()){

for (const auto &face : cell->face_iterators()){

if (face->at_boundary()){

for (const auto v : face->vertex_indices())

cout<<cell->vertex(v)<<" ";

cout<<endl;

}

}

}

We get the following results (after eliminating the repetitive ones):

-1 -1 -0.5 -1
-0.5 -1 0 -1
-1 -0.5 -0.5 -0.5
0 -1 0.5 -1
0.5 -1 1 -1
0.5 -0.5 1 -0.5
-1 0 -0.5 0
-1 0.5 -0.5 0.5
-0.5 0.5 0 0.5
0.5 0 1 0
0 0.5 0.5 0.5
0.5 0.5 1 0.5

which means, instead of these vertices:

we are getting these vertices:

Where did I make a mistake?

Best regards,

Masoud

[Praveen C]

There is a small error in this code.

On 16-Dec-2021, at 5:43 PM, Masoud Ahmadi <masou...@gmail.com> wrote:

for (const auto &cell : dof_handler.active_cell_iterators()){

for (const auto &face : cell->face_iterators()){

if (face->at_boundary()){

for (const auto v : face->vertex_indices())

cout<<cell->vertex(v)<<" ";

cout<<endl;

}

}

}

cout<<cell->vertex(v)<<" “;

should be

cout<<face->vertex(v)<<" “;

best

praveen

[Masoud Ahmadi]

Thanks Praveen.

It was resolved.