On 03/15/2013 02:01 PM, Roy Stogner wrote:
>
> On Fri, 15 Mar 2013, Jens Lohne Eftang wrote:
>
>> I suspect I have not set some important solver flags. Any ideas?
>
> I'd start by turning on PETSc's monitor flags ('-ksp_monitor' etc?).
> Endless residual reevaluations suggests to me that the initial
> linear solve converged poorly and didn't give you a descent direction,
> and a subsequent line search is failing to find a reduced nonlinear
> residual.
It seems to me that the residual gets assembled after the solver has
converged, for some reason. If I turn on -ksp_monitor and use an
iterative solver, I get the following output:
Assembling the residual
PetscDiffSolver step 0, |residual|_2 = 0.403898
Assembling the Jacobian
0 KSP Residual norm 2.618281270280e+00
1 KSP Residual norm 4.606506511583e+00
2 KSP Residual norm 1.293864920956e+01
3 KSP Residual norm 1.466592284831e+01
.
.
.
633 KSP Residual norm 2.463324961881e-05
Linear solve converged due to CONVERGED_RTOL iterations 633
Assembling the residual
Assembling the residual
.
.
.
Assembling the residual (35 times)
> ---
> Roy
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