Hello Wolfgang,
thanks for your message.
May I know which method or keywords can be used to stand for the
non-existing cell and could I use cell->at_boundary() to check whether the
cell exists or not?
I would like to know how we can identify if the object
of dealii::IteratorRange<dealii::TriaActiveIterator<dealii::DoFCellAccessor<3,
3, false> > >::IteratorOverIterators does not exist. I have tried ==NULL
and nullptr, however, it doe snot work.
There is the code snippet below, please take a look:
for (const auto &cell : solid_3d.dof_handler_ref.active_cell_iterators())
{
if(cell->at_boundary()){
continue;
}//to check whether the cell exists
const unsigned int cell_index = cell->active_cell_index();
if (visited_cells[cell_index])
continue; // Skip if the cell has been visited by its all
neighbors
// Loop over all degrees of freedom on the current cell
for (unsigned int i = 0; i < solid_3d.dofs_per_cell; ++i)
{
// Loop over all neighboring cells
for (unsigned int f = 0; f < cell->n_faces(); ++f)
{
auto neighbor = cell->neighbor(f);//find the neighbor ,but not
sure if it exists
if(neighbor->at_boundary())
continue;//check if the neighbor of cell exists
int neighbor_index = neighbor->active_cell_index();//get the
global index of the cell if it exists
...
The whole code can be found via the link :
https://github.com/Lancelof2019/cook_membrane_snippet/blob/main/code_snippet.cpp
Thanks in advance!
Best regards
Lance
Wolfgang Bangerth <bange...@colostate.edu> 于2023年11月28日周二 01:54写道：
>
> On 11/27/23 14:52, Lance Zhang wrote:
> >
> > May I know how to find the neighbor of a cell?
> >
> > Here is one part of my code:
> >
> ----------------------------------------------------------------------------------------------------------------------
> > for (const auto &cell :
> solid_3d.get_dof_handler().active_cell_iterators()
> > {
> > const unsigned int cell_index = cell->active_cell_index();
> >
> > // Loop over all degrees of freedom on the current cell
> > for (unsigned int i = 0; i < dofs_per_cell.dofs_per_cell; ++i)
> > {
> > // Loop over all neighboring cells
> > for (const auto &neighbor : Find_neighbors?)){
>
> You can write this as
> for (unsigned int f=0; f<cell->n_faces(); ++f)
> {
> DoFHandler::cell_iterator neighbor = cell->neighbor(f);
> ...
> }
>
> Best
> W.
>
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