[CIG-SHORT] not convergence for dynamic fault

[翁辉辉]

Hi:
 
   I find some convergence problems, When I use the dynamic fault in the subduction example(only use the fault_slabtop).
It is the partial input about the fault below:

[pylithapp.timedependent.implicit]
solver = pylith.problems.SolverNonlinear

[pylithapp.timedependent.interfaces]
fault_slabtop = pylith.faults.FaultCohesiveDyn
[pylithapp.timedependent.interfaces.fault_slabtop]
label = fault_slabtop
quadrature.cell = pylith.feassemble.FIATSimplex
quadrature.cell.shape = line
friction = pylith.friction.StaticFriction
friction.label = Static friction
friction.db_properties = spatialdata.spatialdb.UniformDB
friction.db_properties.label = Static friction
friction.db_properties.values = [friction-coefficient,cohesion]
friction.db_properties.data = [5.0,0.0*MPa]

  and for the initial stress I set the west boundry's displacement +10m,east boundry's displacement -10m. I use the default SNES linesearch method for the problems,though the  linear solve converges very well (norm< 1e-10),but the SNES fnorm decrease slowly(Fnorm > 1e-2) and some times the line search failed. When I set friction-coefficient very large or very small , it can almost convergence well.Then I think maybe the Jacobian is bad, but can I change that ? 

Thank you very much,

 huihui weng