I can't do that, it's a matshell.
You can use MatComputeExplicitOperator or MatFDColoring to get the entries.
Also, make sure the MATSHELL is really, truly a linear operator. You'll get
very confusing results if you accidentally leave some nonlinearity inside
that function.
Thanks for
What happens if you use -pc_type lu ?
Barry,
I can't do that, it's a matshell.
Chris
On Sep 21, 2012, at 3:29 AM, Klaij, Christiaan C.Klaij at marin.nl wrote:
When I use zero initial guess, GMRES with left PC gives a huge
jump in true resisdual between iteration 0 and 1 and GMRES
I'm solving a system with GMRES using the same preconditioner either on
the left or on the right.
For left preconditioning I get two orders of reduction for the
preconditioned residual in 20 its:
Notice here that your preconditioner is far from one. It manages to
blow
When I use zero initial guess, GMRES with left PC gives a huge
jump in true resisdual between iteration 0 and 1 and GMRES with
right PC is stuck, the solution remains zero, as mentioned before.
When I use the Knoll trick, both issues are gone (!) and I do get
similar results for left and right
What happens if you use -pc_type lu ?
On Sep 21, 2012, at 3:29 AM, Klaij, Christiaan C.Klaij at marin.nl wrote:
When I use zero initial guess, GMRES with left PC gives a huge
jump in true resisdual between iteration 0 and 1 and GMRES with
right PC is stuck, the solution remains zero,
I'm solving a system with GMRES using the same preconditioner either on
the left or on the right.
For left preconditioning I get two orders of reduction for the
preconditioned residual in 20 its:
Notice here that your preconditioner is far from one. It manages to blow
up the true
Is the preconditioner singular? How about the matrix? Is
the preconditioner a linear operator? Did you try KSPFGMRES
on it?
The matrix comes from incompressible Navier-Stokes and the
preconditioner is of Schur complement type (SIMPLE). Both are
shells. FGMRES (and GCR) give the same
On Thu, Sep 20, 2012 at 2:11 AM, Klaij, Christiaan C.Klaij at marin.nl wrote:
I'm solving a system with GMRES using the same preconditioner either on
the left or on the right.
For left preconditioning I get two orders of reduction for the
preconditioned residual in 20 its:
I'm solving a system with GMRES using the same preconditioner either on the
left or on the right.
For left preconditioning I get two orders of reduction for the preconditioned
residual in 20 its:
0 KSP preconditioned resid norm 2.980694554053e+01 true resid norm
7.058057578378e-05
On Wed, Sep 19, 2012 at 10:01 AM, Klaij, Christiaan C.Klaij at marin.nlwrote:
I'm solving a system with GMRES using the same preconditioner either on
the left or on the right.
For left preconditioning I get two orders of reduction for the
preconditioned residual in 20 its:
Notice here that
Is the preconditioner singular? How about the matrix? Is the
preconditioner a linear operator? Did you try KSPFGMRES on it?
On Sep 19, 2012, at 10:01 AM, Klaij, Christiaan C.Klaij at marin.nl wrote:
I'm solving a system with GMRES using the same preconditioner either on the
left or on
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