Thanks!
I'd always wondered why the linear solver parameters aren't part of
the Newton set, so the new rationale makes a lot of sense to me.
One parameter is not accepted by the Newton solver though, being
"symmetric" (which helps choosing an appropriate Krylov solver I
guess). If there's some refactoring going on, I'd vote for make the
choice of the Krylov method explicit, btw ("Explicit is better than
implicit.").
Cheers,
Nico
On Thu, Dec 5, 2013 at 5:59 PM, Anders Logg <[email protected]> wrote:
> As part of fixing that issue, I moved the linear solver parameters
> from NonlinearVariationalSolver down to NewtonSolver, since that is
> where those parameters are used. The nonlinear solver chooses a method
> (Newton), which then needs to solve a linear system and thus has
> options for how to do that. At the same time, this fixed another
> issue, which was that the linear solver parameters could not be
> changed in the Newton solver, if used stand-alone (not from
> NonlinearVariationalSolver).
>
> Nico, simply make the linear_solver parameter into the parameter set
> newton_solver and it should work.
>
> I agree it would be best to change the parameters only once but these
> are two different and relatively unrelated changes: the first one is
> about moving the parameters from one class to another. The other is
> about cleaning up the naming of the parameters/choices for linear
> solvers.
>
> If we can settle on how we want to cleanup the linear solver names,
> then we might want to fix that too before 1.3:
>
> (https://bitbucket.org/fenics-project/dolfin/issue/167/cleanup-of-linear-solver-logic-needed
>
> --
> Anders
>
>
> On Thu, Dec 05, 2013 at 05:42:48PM +0100, Jan Blechta wrote:
>> I was thinking that issue 10 is supposed to be fixed while keeping the
>> interface same in 1.3 and discuss the changes after release. It does
>> not make sense to change the interface twice, both for 1.3 and >= 1.4.
>>
>> Jan
>>
>>
>> On Thu, 5 Dec 2013 17:35:49 +0100
>> Nico Schlömer <[email protected]> wrote:
>>
>> > So apparently,
>> >
>> > solve(F1 == 0, ui,
>> > bcs=u_bcs,
>> > J=J,
>> > solver_parameters={
>> > 'newton_solver':
>> > {'maximum_iterations': 5, 'report': True,
>> > 'absolute_tolerance':
>> > tol, 'relative_tolerance': 0.0
>> > },
>> > 'linear_solver': 'iterative',
>> > 'symmetric': False,
>> > 'preconditioner': 'ilu',
>> > 'krylov_solver':
>> > {'relative_tolerance': tol, 'absolute_tolerance': 0.0,
>> > 'maximum_iterations':
>> > 100, 'monitor_convergence': True}
>> > })
>> >
>> > is not a valid nonlinear solve anymore (suppsedly in connection with
>> > <https://bitbucket.org/fenics-project/dolfin/commits/718f9a59b2b2c315a4c82d91022b74b31329effc>).
>> > How to specify linear solver options now?
>> >
>> > Cheers,
>> > Nico
>> > _______________________________________________
>> > fenics-support mailing list
>> > [email protected]
>> > http://fenicsproject.org/mailman/listinfo/fenics-support
>>
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