Hi, I use ML as a preconditioner for the pressure poisson equation for Stokes problem. I solve for the pressure at each time step with ad DMMGSolve on the whole (Stokes) system. I randomly get the following error at some point.
[0]PETSC ERROR: --------------------- Error Message ------------------------------------ [0]PETSC ERROR: Operation done in wrong order! [0]PETSC ERROR: Number levels already set for MG make sure that you call PCMGSetLevels() before KSPSetFromOptions()! [0]PETSC ERROR: ------------------------------------------------------------------------ [0]PETSC ERROR: Petsc Development HG revision: d1471993ab06fb6a9072f156c420ef0a456a086c HG Date: Sun May 01 09:59:41 2011 -0500 [0]PETSC ERROR: See docs/changes/index.html for recent updates. [0]PETSC ERROR: See docs/faq.html for hints about trouble shooting. [0]PETSC ERROR: See docs/index.html for manual pages. [0]PETSC ERROR: ------------------------------------------------------------------------ [0]PETSC ERROR: ./2dbphlow on a arch-linu named domenico-Dell-System-XPS-L502X by domenico Wed Jun 29 14:32:00 2011 [0]PETSC ERROR: Libraries linked from /opt/petsc-dev/arch-linux2-c-debug/lib [0]PETSC ERROR: Configure run at Thu May 5 03:28:56 2011 [0]PETSC ERROR: Configure options --with-cc=icc --with-fc=ifort --download-f-blas-lapack=1 --download-mpich=1 --download-superlu_dist --download-parmetis --download-mumps --download-blacs --download-scalapack --download-hypre --download-ml --with-c2html=0 --download-prometheus --download-parms [0]PETSC ERROR: ------------------------------------------------------------------------ [0]PETSC ERROR: PCMGSetLevels() line 151 in src/ksp/pc/impls/mg/mg.c [0]PETSC ERROR: PCSetUp_ML() line 610 in src/ksp/pc/impls/ml/ml.c [0]PETSC ERROR: PCSetUp() line 819 in src/ksp/pc/interface/precon.c [0]PETSC ERROR: KSPSetUp() line 261 in src/ksp/ksp/interface/itfunc.c [0]PETSC ERROR: KSPSolve() line 383 in src/ksp/ksp/interface/itfunc.c [0]PETSC ERROR: PCApply_LSC() line 85 in src/ksp/pc/impls/lsc/lsc.c [0]PETSC ERROR: PCApply() line 383 in src/ksp/pc/interface/precon.c [0]PETSC ERROR: FGMREScycle() line 174 in src/ksp/ksp/impls/gmres/fgmres/fgmres.c [0]PETSC ERROR: KSPSolve_FGMRES() line 300 in src/ksp/ksp/impls/gmres/fgmres/fgmres.c [0]PETSC ERROR: KSPSolve() line 426 in src/ksp/ksp/interface/itfunc.c [0]PETSC ERROR: PCApply_FieldSplit_Schur() line 572 in src/ksp/pc/impls/fieldsplit/fieldsplit.c [0]PETSC ERROR: PCApply() line 383 in src/ksp/pc/interface/precon.c [0]PETSC ERROR: FGMREScycle() line 174 in src/ksp/ksp/impls/gmres/fgmres/fgmres.c [0]PETSC ERROR: KSPSolve_FGMRES() line 300 in src/ksp/ksp/impls/gmres/fgmres/fgmres.c [0]PETSC ERROR: KSPSolve() line 426 in src/ksp/ksp/interface/itfunc.c [0]PETSC ERROR: SNES_KSPSolve() line 3124 in src/snes/interface/snes.c [0]PETSC ERROR: SNESSolve_LS() line 190 in src/snes/impls/ls/ls.c [0]PETSC ERROR: SNESSolve() line 2424 in src/snes/interface/snes.c [0]PETSC ERROR: DMMGSolveSNES() line 503 in src/snes/utils/damgsnes.c [0]PETSC ERROR: DMMGSolve() line 313 in src/snes/utils/damg.c [0]PETSC ERROR: main() line 726 in 2dbphlow.c application called MPI_Abort(MPI_COMM_WORLD, 1) - process 0 [cli_0]: aborting job: application called MPI_Abort(MPI_COMM_WORLD, 1) - process 0 ===================================================================================== = BAD TERMINATION OF ONE OF YOUR APPLICATION PROCESSES = EXIT CODE: 256 = CLEANING UP REMAINING PROCESSES = YOU CAN IGNORE THE BELOW CLEANUP MESSAGES ===================================================================================== I don't know the reason for it, it occurs at some random timestep if I change any of the input parameters like the viscosity, the geometry, the mesh size etc... Sometimes it just doesn't occur at all. ML is used with the following options: -stokes_fieldsplit_pressure_lsc_pc_type ml \ -stokes_fieldsplit_pressure_lsc_pc_ml_maxCoarseSize 1 \ -stokes_fieldsplit_pressure_lsc_pc_ml_Threshold 0.009 \ -stokes_fieldsplit_pressure_lsc_pc_ml_Symmetrize\ -stokes_fieldsplit_pressure_lsc_pc_ml_KeepAggInfo\ -stokes_fieldsplit_pressure_lsc_pc_ml_Reusable\ -stokes_fieldsplit_pressure_lsc_pc_ml_DampingFactor 1.3333 \ Any idea?