[CIG-SHORT] Applying Gravitational Forces with Pylith

[Brad Aagaard]

Is this the gravity only problem to compute the initial stresses? If so, 
then you should remove the fault.

On 08/01/2018 08:59 PM, Niloufar Abolfathian wrote:
> Thanks, Charles.
> 
> My error is due to the convergence of the nonlinear solver. I have made 
> some modifications but not sure if it is a good idea to decrease my 
> residual norms.
> 
> Best,
> Niloufar
> 
> 
> This is the setting I am using:
> 
> 
> [pylithapp.timedependent]
> formulation =pylith.problems.ImplicitLgDeform
> 
> 
> [pylithapp.timedependent.formulation]
> output =[domain,subdomain]
> output.subdomain =pylith.meshio.OutputSolnSubset
> solver =pylith.problems.SolverNonlinear
> 
> [pylithapp.timedependent.formulation.time_step]
> total_time =50000.0*year
> dt =2.0*year
> 
> [pylithapp.timedependent.interfaces]
> fault =pylith.faults.FaultCohesiveDyn
> 
> [pylithapp.timedependent.interfaces.fault]
> label =fault
> edge =fault_edge
> zero_tolerance =1.0e-11
> 
> # Use the slip-weakening friction model.
> friction.db_properties =spatialdata.spatialdb.UniformDB
> friction.db_properties.label =Slip weakening
> friction.db_properties.values 
> =[static-coefficient,dynamic-coefficient,slip-weakening-parameter,cohesion]
> 
> friction.db_properties.data =[0.6,0.4,0.2*m,0.0*Pa]
> 
> # ----------------------------------------------------------------------
> # PETSc settings
> # ----------------------------------------------------------------------
> [pylithapp.petsc]
> malloc_dump =
> 
> # Preconditioner settings.
> pc_type =asm
> sub_pc_factor_shift_type =nonzero

When you encounter convergence errors, a good strategy is to revert to 
the direct solver. Note that this only works when you don't have a fault.

pc_type = lu


For most real applications (after you have debugged the setup)l, we 
recommend using the multigrid preconditioner. See 
solver_algebraicmultigrid.cfg (no fault) and solver_fieldsplit.cfg )with 
fault) in examples/3d/subduction.

> 
> # Friction sensitivity solve used to compute the increment in slip
> # associated with changes in the Lagrange multiplier imposed by the
> # fault constitutive model.
> friction_pc_type =asm
> friction_sub_pc_factor_shift_type =nonzero
> friction_ksp_max_it =50
> friction_ksp_gmres_restart =30
> 
> # Uncomment to view details of friction sensitivity solve.
> #friction_ksp_monitor = true
> #friction_ksp_view = true
> friction_ksp_converged_reason =true
> 
> # Reduce convergence tolerances.
> ksp_rtol =1.0e-16
> ksp_atol =1.0e-12
> ksp_max_it =4000
> ksp_gmres_restart =100
> 
> snes_rtol =1.0e-9
> snes_atol =1.0e-8
> snes_max_it =4000
>