Simon:
Unfortunately, the program results in a segmentation fault. Specifically, no
exception (TrilinosWrappers::SolverDirect::ExcTrilinosError) is thrown when
the matrix containing NaN values is passed to the solver's solve function.
If you run the program in a debugger, can you find out where the segfault
happens?
In contrast, when running a sequential program with SparseDirectUMFPACK, the
solver correctly handles the issue, and I am able to catch the exception
SparseDirectUMFPACK::ExcUMFPACKError.
Can this be considered a Trilinos bug? Has this issue been addressed in newer
versions of deal.II or Trilinos?
Segfaults should never happen. Better error messages are always better, but I
don't know whether this has been addressed. Perhaps this is your chance to try
a newer version of deal.II? ;-)
Clearly, assigning NaN values to a matrix does not make much sense. However,
in the optimized release version of my program, bad inputs can occasionally
lead to cases where the cell matrix contains NaN values. In such situations, I
rely on catching exceptions (e.g., from SparseDirectUMFPACK) to handle the
error gracefully.
Perhaps a better approach than seeing whether a linear solver succeeds would
be to first check whether the matrix/rhs have NaNs before you hand them off to
the solver. This can be done cheaply via the Vector::l1_norm() and
SparseMatrix::frobenius_norm() functions that simply add up the (squares) or
entries. If the result is NaN, you know something is amiss.
Best
W.
--
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Wolfgang Bangerth email: bange...@colostate.edu
www: http://www.math.colostate.edu/~bangerth/
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