Re: [Libmesh-users] try-catch in a PETSc solve()

[Salazar De T. M. <sal...@ll...>]

The petsc options for the system are as follows:


-Elasticity_ksp_monitor_true_residual
-Elasticity_ksp_converged_reason
-Elasticity_ksp_type cg
-Elasticity_log_view
-Elasticity_mg_levels_esteig_ksp_type cg
-Elasticity_mg_levels_ksp_chebyshev_esteig_steps 50
-Elasticity_mg_levels_ksp_type chebyshev
-Elasticity_mg_levels_pc_type sor
-Elasticity_pc_type gamg
-Elasticity_pc_gamg_verbose 7
-Elasticity_pc_gamg_type agg
-Elasticity_pc_gamg_agg_nsmooths 1
-Elasticity_pc_gamg_threshold 0.001
-Elasticity_snes_linesearch_type basic
-Elasticity_snes_atol 1e-6
-Elasticity_ksp_atol 1e-7
-Elasticity_ksp_rtol 1e-9
-Elasticity_ksp_norm_type unpreconditioned


I pass the rigid body modes to the solver.

________________________________
From: Jed Brown <je...@je...>
Sent: Saturday, November 11, 2017 1:43:32 PM
To: Salazar De Troya, Miguel; lib...@li...
Subject: Re: [Libmesh-users] try-catch in a PETSc solve()

What is your error message?  If the error is raised in PETSc, there is
usually a setting to make it return without raising an error (instead
setting a "diverged" reason).

"Salazar De Troya, Miguel" <sal...@ll...> writes:

> Hello
>
>
> I have an optimization problem for which at a certain iteration, PETSc fails to build the preconditioner. I would like to catch that error and print my EquationSystem to disk so I can rerun the PETSc solve at that optimization iteration from the start. I cannot just rerun my optimization and write to disk at the iteration I know it is going to fail. The reason is that in parallel the optimization slightly differs every time I run it so the iteration it is going to fail at keeps changing. Maybe something along this lines:
>
>
> try{
>
>     system.solve()
>
> }
>
> catch(...){
>
>    EquationSystem & es = system.get_equation_systems();
>
>    es.write("eq_output.xdr")
>
> }
>
>
> Thanks
>
> Miguel
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