[petsc-users] TS and petscFE -unable to access u_t

[Maximilian Hartig]

Thank you,

I used these routines to setup a CN type TS. The problem I face now is that I seem to be unable to access the temporal derivatives u_t[..] for the definition of the residuals. I get a segmentation violation inside the  PetscFEIntegrateResidual routine whenever I try to. I have attached the error message below.
Also, I am wondering whether it is possible to update the neumann boundary condition of the FE object for each timestep. This would be useful for coupling purposes.

Thank you,

Max


[0]PETSC ERROR: ------------------------------------------------------------------------
[0]PETSC ERROR: Caught signal number 11 SEGV: Segmentation Violation, probably memory access out of range
[0]PETSC ERROR: Try option -start_in_debugger or -on_error_attach_debugger
[0]PETSC ERROR: or see http://www.mcs.anl.gov/petsc/documentation/faq.html#valgrind
[0]PETSC ERROR: or try http://valgrind.org on GNU/linux and Apple Mac OS X to find memory corruption errors
[0]PETSC ERROR: likely location of problem given in stack below
[0]PETSC ERROR: ---------------------  Stack Frames ------------------------------------
[0]PETSC ERROR: Note: The EXACT line numbers in the stack are not available,
[0]PETSC ERROR:       INSTEAD the line number of the start of the function
[0]PETSC ERROR:       is given.
[0]PETSC ERROR: [0] PetscFEIntegrateResidual_Basic line 3503 /Users/maxhartig/PETSc/src/dm/dt/interface/dtfe.c
[0]PETSC ERROR: [0] PetscFEIntegrateResidual line 5753 /Users/maxhartig/PETSc/src/dm/dt/interface/dtfe.c
[0]PETSC ERROR: [0] DMPlexComputeResidual_Internal line 1706 /Users/maxhartig/PETSc/src/snes/utils/dmplexsnes.c
[0]PETSC ERROR: [0] DMPlexSNESComputeResidualFEM line 2152 /Users/maxhartig/PETSc/src/snes/utils/dmplexsnes.c
[0]PETSC ERROR: [0] SNESComputeFunction_DMLocal line 65 /Users/maxhartig/PETSc/src/snes/utils/dmlocalsnes.c
[0]PETSC ERROR: [0] SNES user function line 2144 /Users/maxhartig/PETSc/src/snes/interface/snes.c
[0]PETSC ERROR: [0] SNESComputeFunction line 2129 /Users/maxhartig/PETSc/src/snes/interface/snes.c
[0]PETSC ERROR: [0] SNESSolve_NEWTONLS line 150 /Users/maxhartig/PETSc/src/snes/impls/ls/ls.c
[0]PETSC ERROR: [0] SNESSolve line 3961 /Users/maxhartig/PETSc/src/snes/interface/snes.c
[0]PETSC ERROR: [0] TS_SNESSolve line 188 /Users/maxhartig/PETSc/src/ts/impls/implicit/theta/theta.c
[0]PETSC ERROR: [0] TSStep_Theta line 206 /Users/maxhartig/PETSc/src/ts/impls/implicit/theta/theta.c
[0]PETSC ERROR: [0] TSStep line 3700 /Users/maxhartig/PETSc/src/ts/interface/ts.c
[0]PETSC ERROR: [0] TSSolve line 3921 /Users/maxhartig/PETSc/src/ts/interface/ts.c
[0]PETSC ERROR: --------------------- Error Message --------------------------------------------------------------
[0]PETSC ERROR: Signal received
[0]PETSC ERROR: See http://www.mcs.anl.gov/petsc/documentation/faq.html for trouble shooting.
[0]PETSC ERROR: Petsc Release Version 3.7.2, unknown 
[0]PETSC ERROR: Configure options --download-triangle
[0]PETSC ERROR: #1 User provided function() line 0 in  unknown file
application called MPI_Abort(MPI_COMM_WORLD, 59) - process 0
[unset]: write_line error; fd=-1 buf=:cmd=abort exitcode=59

> On 03 Aug 2016, at 16:44, Matthew Knepley <knepley at gmail.com> wrote:
> 
> On Tue, Aug 2, 2016 at 8:22 AM, Maximilian Hartig <imilian.hartig at gmail.com <mailto:imilian.hartig at gmail.com>> wrote:
> Hello all,
> 
> I would like to run a transient problem with PetscFE. Example ex11.c seems relevant since it uses the PestcFV context to create boundary conditions and RHS Functions for the TS.
> Is there an easy way to do transient analysis with TS and petscFE or do I have to code my own time-stepping routine?
> 
> You can use
> 
>     ierr = DMTSSetBoundaryLocal(adaptedDM,  DMPlexTSComputeBoundary, user);CHKERRQ(ierr);
>     ierr = DMTSSetIFunctionLocal(adaptedDM, DMPlexTSComputeIFunctionFEM, user);CHKERRQ(ierr);
>     ierr = DMTSSetIJacobianLocal(adaptedDM, DMPlexTSComputeIJacobianFEM, user);CHKERRQ(ierr);
> 
> I have been meaning to write a heat equation example, but I have not finished yet,
> 
>   Thanks,
> 
>      Matt
>  
> Thanks,
> Max
> 
> 
> 
> -- 
> What most experimenters take for granted before they begin their experiments is infinitely more interesting than any results to which their experiments lead.
> -- Norbert Wiener

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