[petsc-users] Modified Taylor-Hood elements with piece-wise constant pressure for Stokes equation

[Justin Chang]

I originally solve that example problem using LU. But when I solve this one:

http://fenicsproject.org/documentation/dolfin/1.5.0/python/demo/documented/stokes-iterative/python/documentation.html

By simply running their code as is for TH and adding the one like I
mentioned for MTH, I get the following outputs when I pass in -ksp_monitor
-ksp_view and -log_summary

The latter obviously takes a greater amount of time and iterations to
converge, and it was using the solver and precondition options that was
originally designed for P2/P1. I haven't experimented around with this
fully yet.

Thanks,
Justin

On Tue, Jun 2, 2015 at 1:19 PM, Jed Brown <jed at jedbrown.org> wrote:

> Lawrence Mitchell <lawrence.mitchell at imperial.ac.uk> writes:
> > Maybe Justin can chime in here, I don't know, I just happened to know
> > how the fenics implementation produces the "basis", so proffered that.
>
> Thanks, Lawrence.  Unfortunately, my original questions remain
> unanswered and now I'm doubly curious why FEniCS appears not to fail due
> to the singular linear system.
>
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