On 7/23/20 10:42 AM, Pascal Kraft wrote:
I have Trillions compiled with support for complex numbers and also searched
through the LinearAlgebra documentation.
I don't think I knew that one can compile Trilinos with complex numbers. How
do you do that?
It does not greatly surprise me that we use TrilinosScalar and double
interchangeably. If Trilinos can indeed be compiled with complex numbers, then
we ought to find a way to (i) make TrilinosScalar dependent on whatever
Trilinos was compiled for, (ii) ensure that all of the places that currently
don't compile because we use double in place of TrilinosScalar are fixed.
Patches are, as always, very welcome!
I require GMRES as a solver (which should be possible, because the GMRES
Versions all use a templated Vector which can take complex components) and MPI
distribution of a sparse system. I have so far only seen FullMatrix to accept
complex numbers.
I believe that GMRES could indeed be made to work for complex-valued problems,
but I'm not sure any of us have every tried. When writing step-58, I toyed
with the idea of looking up in the literature what one would need for a
complex GMRES, but in the end decided to just make SparseDirectUMFPACK work
instead. The issue is that for every matrix-vector and vector-vector operation
that happens inside GMRES, you have to think about whether one or the other
operand needs to be complex-conjugated. I'm certain that is possible, but
would require an audit of a few hundred lines. It would probably be simpler to
just use PETSc's (or Trilinos') GMRES implementation.
Best
W.
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Wolfgang Bangerth email: bange...@colostate.edu
www: http://www.math.colostate.edu/~bangerth/
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