Here is perhaps a minimaler (non)working example:
#include <deal.II/grid/tria.h> #include <deal.II/grid/grid_generator.h> #
include <deal.II/grid/grid_refinement.h> #include
<deal.II/dofs/dof_handler.h> #include <deal.II/dofs/dof_tools.h> #include
<deal.II/fe/fe_dgq.h> #include <deal.II/lac/vector.h> #include
<deal.II/numerics/vector_tools.h> using namespace dealii; int main() {
FE_DGQ<2> fe(0); Triangulation<2> trig; Triangulation<2> trig_child;
GridGenerator::hyper_cube(trig); trig.refine_global(1);
trig_child.copy_triangulation(trig); trig_child.refine_global(1);
DoFHandler<2> dof_handler(trig); dof_handler.distribute_dofs(fe); Vector<int>
ref_level({1,2,3,4}); // ref_level is the vector on // the coarser mesh trig
DoFHandler<2> dof_handler_child(trig_child);
dof_handler_child.distribute_dofs(fe); Vector<int>
ref_level_child(dof_handler_child.n_dofs()); // ref_level_child is the
vector // on the finer mesh trig_child
VectorTools::interpolate_to_different_mesh(dof_handler, ref_level,
dof_handler_child, ref_level_child); }
And I just found that the bug comes from feeding Vector<int> to
interpolate_to_different_mesh() while int is not a valid
VectorType::value_type therein. Changing int to double fixes it.
Best,
Yuan
On Friday, November 10, 2023 at 7:48:11 PM UTC Yuan Wang wrote:
> Hi Peter,
>
> Thanks a lot for your help! I was trying to implement a MWE with the first
> method you suggested. However, the function
> VectorTools::interpolate_to_different_mesh() seems to be causing a linker
> error:
>
> /home/usrname/Projects/hdg_dealii/adr/ip/multilevel_refinement/MultilevelRefinement.cc:
> 66: error: undefined reference to 'void
> dealii::VectorTools::interpolate_to_different_mesh<2, 2,
> dealii::Vector<int> >(dealii::DoFHandler<2, 2> const&, dealii::Vector<int>
> const&, dealii::DoFHandler<2, 2> const&, dealii::Vector<int>&)' collect2:
> error: ld returned 1 exit status make[2]: ***
> [CMakeFiles/MultilevelRefinement.dir/build.make:133:
> MultilevelRefinement] Error 1 make[1]: *** [CMakeFiles/Makefile2:90:
> CMakeFiles/MultilevelRefinement.dir/all] Error 2 make: *** [Makefile:91:
> all] Error 2
>
> Here is, I think, the relevant chunk of code (original code file is also
> attached):
> // ... #include <deal.II/numerics/vector_tools.h> // ...
> Triangulation<dim> triangulation_old;
> triangulation_old.copy_triangulation(triangulation); DoFHandler<dim>
> dof_handler_old(triangulation_old); dof_handler_old.distribute_dofs(fe);
> Vector<int> ref_level_old(ref_level);
> triangulation.execute_coarsening_and_refinement();
> dof_handler.reinit(triangulation); dof_handler.distribute_dofs(fe);
> ref_level.reinit(dof_handler.n_dofs());
> VectorTools::interpolate_to_different_mesh(dof_handler_old, ref_level_old,
> dof_handler, ref_level); // ...
>
> Can you help shed some light on this?
>
> Best regards,
>
> Yuan
>
> On Thursday, November 9, 2023 at 6:25:45 AM UTC [email protected] wrote:
>
>> Hi Greg,
>>
>> I guess what you could do is to treat the vector as vector associated
>> with a DoFHandler with FE_DGQ(0). During each refinement you "interpolate"
>> the vector to the new mesh and decrease the value by one. This approach
>> naturally extends to a parallel setting.
>>
>> Alternately, you could create a single vector associated the coarse cells
>> and while looping over active cells of the refined mesh you would
>> recursively call the parent cell until you reach the coarsest cell whose id
>> you can use to access the vector. In the parallel setting, the vector
>> associated to the coarse cells would need to replicated between processes.
>>
>> Hope this help,
>> PM
>>
>> On Thursday, 9 November 2023 at 03:32:42 UTC+1 [email protected] wrote:
>>
>>> Dear all,
>>>
>>> This might be a somewhat odd feature request but I was wondering whether
>>> the functionality described below can be readily achieved in deal.II
>>> already:
>>>
>>> Say we are given a coarse mesh with every cell never refined, and a
>>> vector of non-negative integers associated with each cell. The integer is
>>> the level of isotropic refinement to be applied to each cell. The number
>>> can be 0, which means not doing anything here; it can be 1, which
>>> corresponds to what set_refine_flag() does. But it can also be any
>>> number bigger than 1. Say we have a quadrilateral cell and the number
>>> associated with it is 2, then the cell is to be refined isotropically once
>>> into four children and then every child is refined again, resulting in 16
>>> grandchildren.
>>>
>>> If we were to hard code this, would it be sound to simply rely on
>>> set_refine_flag() and execute the refinement one level after another
>>> for M levels, with M being the maximum number of the given vector? And
>>> perhaps to do this we would need iterators triangulation.begin(n),
>>> triangulation.end(n) and isotropic_child() involved somehow?
>>>
>>> Any help and/or pro tips would be greatly appreciated!
>>>
>>> Best regards,
>>> Yuan
>>>
>>>
>>
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