[CIG-SHORT] Problems with viscoelastic model with Pylith

[Francisco Delgado]

Thanks Brad, I'll give it a try

On Wed, Jul 12, 2017 at 3:17 PM, Brad Aagaard <baagaard at usgs.gov> wrote:

> Francisco,
>
> Check to make sure the solver is converging at every time step. This is
> easiest if you include
>
> ksp_error_if_not_converged = true
>
> so that the simulation will abort with an error if convergence is not
> reached.
>
> If you still don't understand what the problem is, send a sketch/diagram
> of the problem you are trying to solve along with the
> pylith_parameters.json file generated (which contains all of your
> parameters).
>
> Regards.
> Brad
>
>
>
>
> On 07/12/2017 11:49 AM, Francisco Delgado wrote:
>
>> Dear Pylith developers,
>>
>> I've been running simulations of a pressurised magma chamber surrounded
>> by a viscoelastic shell with an exponential pressure function of the form
>> P=Pf(1-exp(-t/tau)) but the solutions yields numerical instabilities like
>> in the attached plot. I suspect it's an issue with the solver, but I don't
>> know what to look for. My solver parameters are the following which work
>> well for static linear elastic problems
>>
>> [pylithapp.petsc]
>>
>> # Preconditioner settings.
>>
>> pc_type = asm
>>
>> sub_pc_factor_shift_type = nonzero
>>
>> # Convergence parameters.
>>
>> ksp_rtol = 1.0e-12
>>
>> ksp_atol = 1.0e-12
>>
>> ksp_max_it = 500
>>
>> ksp_gmres_restart = 50
>>
>> # Linear solver monitoring options.
>>
>> ksp_monitor = true
>>
>> ksp_view = true
>>
>> ksp_converged_reason = true
>>
>> log_summary = true
>>
>> # start_in_debugger = true
>>
>>
>>
>> Any insight is appreciated
>>
>> Thanks
>>
>> --
>> --------------------------------------------------------
>> Francisco Delgado
>> PhD candidate, Geological Sciences
>> Cornell University
>>
>
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-- 
--------------------------------------------------------
Francisco Delgado
PhD candidate, Geological Sciences
Cornell University
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