On 12/13/2016 02:54 PM, Hamed Babaei wrote:
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."
Hamed -- did you read "the discussion below"? It spells out alternatives you
can use.
Best
W.
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Wolfgang Bangerth email: bange...@colostate.edu
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