Dear Prof. Bangerth, I thank you for your kind and quick response. I see! Here is a minimal self contained example to recreate the issue:
- import a rectangular mesh - define two dof_handlers - attach FE_Q(1) and FE_Q(2) elements respectively - Define two PETScWrappers::MPI::Vector WITH ghost values. All zeros. - Perform FETools::interpolate - [ERROR message] see previous post I provided a CMakeLists.txt, the mesh.msh and a minimalistic README with compile instruction as well. You find all in the attached zip file. I will also try now to submit it as a bug on the github repo. I would enormously appreciate any suggestion on how to either: - fix the issue - (most likely) work around it, until somebody more expert than me fixes it in a future release. Mit freundlichen Grüßen aus Heidelberg, Matteo Malvestiti Il giorno sabato 18 gennaio 2025 alle 01:40:36 UTC+1 Wolfgang Bangerth ha scritto: > On 1/17/25 04:09, Matteo Malvestiti wrote: > > I've read in another discussion here on the user group, that interpolate > > should take in ghosted vectors, but I get an error as soon as I try that. > > Specifically, if I do: > > > > PETScWrappers::MPI::Vector > > locally_relevant_dual_solution_on_primal( > > PrimalSolver<dim>::locally_owned_dofs, > > PrimalSolver<dim>::locally_relevant_dofs, > > PrimalSolver<dim>::mpi_communicator); // with NO GHOST elements > > > > FETools::interpolate(DualSolver<dim>::dof_handler, > > DualSolver<dim>::locally_relevant_solution, > > PrimalSolver<dim>::dof_handler, > > > > PrimalSolver<dim>::linear_system_ptr->hanging_node_constraints, > > locally_relevant_dual_solution_on_primal); > > > > I then get the following error (even just in serial execution): > > > > An error occurred in line <941> of file > > > </var/folders/8z/hlb6vc015qjggytkxn84m6_c0000gn/T/heltai/spack-stage/spack-stage-dealii-9.6.0-rc1-3efkxbxl3aseiejk73xqv2r4jrvgva4l/spack-spc/include/deal.II/lac/pe > > > > tsc_vector_base.h> in function > > > > const VectorReference dealii::PETScWrappers: :internal: > > :VectorReference: :operator+=(const PetscScalar &) const > > > > The violated condition was: > > > > !vector.has_ghost_elements) > > > > Additional information: > > > > > > You are trying an operation on a vector that is only allowed if the > vector has > > no ghost elements, but the vector you are operating on does have ghost > elements. > > > > Specifically, there are two kinds of operations that are typically not > allowed > > on vectors with ghost elements. First, vectors with ghost elements are > > read-only and cannot appear in operations that write into these vectors. > > Second, reduction operations (such as computing the norm of a vector, or > > taking dot products between vectors) are not allowed to ensure that each > > vector element is counted only once (as opposed to once for the owner of > the > > element plus once for each process on which the element is stored as a > ghost > > copy). > > > > > > See the glossary entry on 'Ghosted vectors' for more > > > > > > Can someone more expert than me help to understand how I should face > > interpolations? > > Matteo, > Thanks for reporting this! > > It is entirely possible that this function has simply never been tried > with > parallel triangulations. I know that it was written several years before > we > ever started implementing parallel computations. > > A good first step would be to create a "minimal working example" -- a > complete, compilable code that only sets up data structures and then calls > the > function in question to demonstrate the error. The content of the vectors > you > pass in is not important, they might as well be zero vectors. > > Would you be willing to come up with such a piece of code and submit it as > a > bug to the github repository? I can't promise that anyone has the capacity > to > actually fix the issue, but we can at least tell you where one might have > to > look to fix it! > > Best > Wolfgang > > -- > ------------------------------------------------------------------------ > Wolfgang Bangerth email: bang...@colostate.edu > www: http://www.math.colostate.edu/~bangerth/ > > > -- The deal.II project is located at http://www.dealii.org/ For mailing list/forum options, see https://groups.google.com/d/forum/dealii?hl=en --- You received this message because you are subscribed to the Google Groups "deal.II User Group" group. To unsubscribe from this group and stop receiving emails from it, send an email to dealii+unsubscr...@googlegroups.com. To view this discussion visit https://groups.google.com/d/msgid/dealii/5c57d3de-a061-4f47-bc3d-8cbfc0d0204en%40googlegroups.com.
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