Hi all, I have used* constraints.condense* function in a serial code to apply periodic constraints on system_matrix and system_rhs after their assembly in which I do not use *constraints.distribute_local_to_global* for cell_matrix and cell_rhs but I first assemble mass_matrix , laplace_matrix, nl_matrix and nl_term (the same approach as in step-25) and then syetem_matrix and system_rhs are obtained after some manipulations on the mentioned assembled matrices and vectors.
The problem is that* constraints.condense* doesn't work with *TrilinosWrappers::SparseMatrix *so the question is when we can not use *constraints.distribute_local_to_global *how we can apply constraints in the assembly for parallel codes. In the https://www.dealii.org/8.4.1/doxygen/deal.II/group__constraints.html <https://www.google.com/url?q=https%3A%2F%2Fwww.dealii.org%2F8.4.1%2Fdoxygen%2Fdeal.II%2Fgroup__constraints.html&sa=D&sntz=1&usg=AFQjCNHazlbNq8-QxRUDRTTpEWHT5IXCdg> the following is mentioned which I can't truly understand. "The condensation functions exist for different argument types: SparsityPattern <https://www.dealii.org/8.4.1/doxygen/deal.II/classSparsityPattern.html>, SparseMatrix <https://www.dealii.org/8.4.1/doxygen/deal.II/classSparseMatrix.html> and BlockSparseMatrix <https://www.dealii.org/8.4.1/doxygen/deal.II/classBlockSparseMatrix.html>. Note that there are no versions for arguments of type PETScWrappers::SparseMatrix() <https://www.dealii.org/8.4.1/doxygen/deal.II/classPETScWrappers_1_1SparseMatrix.html> or any of the other PETSc or Trilinos matrix wrapper classes. This is due to the fact that it is relatively hard to get a representation of the sparsity structure of PETSc matrices, and to modify them efficiently; this holds in particular, if the matrix is actually distributed across a cluster of computers. If you want to use PETSc/Trilinos matrices, you can either copy an already condensed deal.II matrix, or assemble the PETSc/Trilinos matrix in the already condensed form, see the discussion below." Thanks and regards, Hamed -- 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 [email protected]. For more options, visit https://groups.google.com/d/optout.
