> "All functions take a sparse matrix object to hold the matrix to be
> created. The functions assume that the matrix is initialized with a
> sparsity pattern (SparsityPattern) corresponding to the given degree
> of freedom handler, i.e. the sparsity structure is already as needed.
> You can do this by calling the DoFTools::make_sparsity_pattern()
> function."
>
> But PETSc handles the sparsity pattern. Can I still use these functions?
No, but for a different reason: the functions currently take an object of type
SparseMatrix to hold the matrix, whereas you want to use a
PETScWrappers::MPI::SparseMatrix object. The functions also do not take into
account that in a parallel context (when you use MPI), not every machine has
to build the entire matrix, so they may not be your best choice anyway.
That said, since the Laplace matrix is so simple to build, it should be easy
for you to write the equivalent of this class using the techniques of step-17
(MPI, PETSc) and step-6 (Laplace equation).
Best
Wolfgang
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Wolfgang Bangerth email: [EMAIL PROTECTED]
www: http://www.math.tamu.edu/~bangerth/
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