[Libmesh-users] libmesh 0.8.0 build on Titan - unknown type name 'idxtype'

Hi, I'm having trouble when the build gets to Parmetis. Everything before that looks fine. config.log is attached. I'm trying this on Titan... it used to work on Jaguar. Not sure what has changed. parmetislib.h and parmetis.h are in the parmetis/Lib I haven't run into this problems before on othe

Re: [Libmesh-users] Newton iteration

Hey Lorenzo, If you believe that your matrix should be invertible and lu should work, try giving PETSc the following options, -pc_type lu -pc_factor_mat_solver_package superlu -pc_factor_nonzeros_along_diagonal To my knowledge this is the most stable lu factorization routine in

Re: [Libmesh-users] Newton iteration

A couple of things: 1. -pre is just an option for that particular example. It was an attempt to provide a solver agnostic way of turning on preconditioning. If you don't specify -pre or a petsc option to turn on preconditioning then you are doing zero preconditioning... which is bound to fail.

Re: [Libmesh-users] Newton iteration

For nonlinear problems the linesearch may very well fail if the linear update is a bad descent direction (usually indicating a nonconvexity of the corresponding energy functional, if it exists; is this a p-Laplacian problem? To the best of my knowledge it is convex for p > 1, albeit the PDE is not

Re: [Libmesh-users] Newton iteration

On Thu, Mar 7, 2013 at 9:31 AM, Subramanya Gautam Sadasiva < ssada...@purdue.edu> wrote: > Yes, that is right... my bad.. > Nevertheless, I think you are correct that there is *something* wrong with his Jacobian. Maybe it's "good enough" to work with non-direct solvers but fails on LU? -- Joh

[Libmesh-users] Solver stops dead with a Cahn Hilliard Navier Stokes system when using adaptivity,

Hi, I am trying to implement a cahn-hilliard navier stokes solver using libMesh. I got the whole thing working without adaptivity. When I add adaptivity to the mix though - the cahn hilliard part of the system solves without any problems, however, when I get to the navier stokes part the solver

Re: [Libmesh-users] Newton iteration

Yes, that is right... my bad.. Subramanya Sadasiva "But memory eventually fades. Turbulences damp out, internal strains yield to plastic flow, concentration inhomogeneities diffuse to uniformity. Systems tend to subside to very simple states,independent of their specific history." Herbert Call

Re: [Libmesh-users] Newton iteration

On Thu, Mar 7, 2013 at 9:20 AM, Subramanya Gautam Sadasiva < ssada...@purdue.edu> wrote: > Hi Lorenzo , > Again, this just suggests to me that lu is not appropriate to your system. > You might have zeros on your diagonals and the petsc lu does not pivot. > If this was the case, wouldn't he see an

Re: [Libmesh-users] Newton iteration

Hi Lorenzo , Again, this just suggests to me that lu is not appropriate to your system. You might have zeros on your diagonals and the petsc lu does not pivot. One solution is to try -pc_factor_shift_positive_definite Subramanya Sadasiva "But memory eventually fades. Turbulences damp out, int

Re: [Libmesh-users] Newton iteration

Hi, My problem converges using: -pre -snes_type ls -snes_type basic but I still get divergence if I add to the above options the direct linear solver: -ksp_type preonly -pc_type lu This looks suspicious to me, also because I get divergence if I delete the "-pre" option (also with iterative l