On Wed, Mar 8, 2017 at 10:47 AM, Kong, Fande <fande.k...@inl.gov> wrote:
> Thanks Barry, > > We are using "KSPSetPCSide(ksp, pcside)" in the code. I just tried > "-ksp_pc_side right", and petsc did not error out. > > I like to understand why CG does not work with right preconditioning? > Mathematically, the right preconditioning does not make sense? > cd src/snes/examples/tutorials knepley/feature-plasma-example $:/PETSc3/petsc/petsc-dev/src/snes/examples/tutorials$ ./ex5 -ksp_view -ksp_type cg -ksp_pc_side right -ksp_error_if_not_converged KSP Object: 1 MPI processes type: cg maximum iterations=10000, initial guess is zero tolerances: relative=1e-05, absolute=1e-50, divergence=10000. right preconditioning using NONE norm type for convergence test PC Object: 1 MPI processes type: ilu out-of-place factorization 0 levels of fill tolerance for zero pivot 2.22045e-14 matrix ordering: natural factor fill ratio given 1., needed 1. Factored matrix follows: Mat Object: 1 MPI processes type: seqaij rows=16, cols=16 package used to perform factorization: petsc total: nonzeros=64, allocated nonzeros=64 total number of mallocs used during MatSetValues calls =0 not using I-node routines linear system matrix = precond matrix: Mat Object: 1 MPI processes type: seqaij rows=16, cols=16 total: nonzeros=64, allocated nonzeros=64 total number of mallocs used during MatSetValues calls =0 not using I-node routines [0]PETSC ERROR: --------------------- Error Message -------------------------------------------------------------- [0]PETSC ERROR: [0]PETSC ERROR: KSPSolve has not converged [0]PETSC ERROR: See http://www.mcs.anl.gov/petsc/documentation/faq.html for trouble shooting. [0]PETSC ERROR: Petsc Development GIT revision: v3.7.5-3127-ge9f6087 GIT Date: 2017-02-11 13:06:34 -0600 [0]PETSC ERROR: ./ex5 on a arch-c-exodus-master named MATTHEW-KNEPLEYs-MacBook-Air-2.local by knepley Wed Mar 8 11:17:43 2017 [0]PETSC ERROR: Configure options --PETSC_ARCH=arch-c-exodus-master --download-chaco --download-cmake --download-ctetgen --download-eigen --download-exodusii --download-gmp --download-hdf5 --download-metis --download-mpfr --download-mpich --download-netcdf --download-p4est --download-parmetis --download-pragmatic --download-triangle --useThreads=1 --with-cc="/Users/knepley/MacSoftware/bin/ccache gcc -Qunused-arguments" --with-cxx="/Users/knepley/MacSoftware/bin/ccache g++ -Qunused-arguments" --with-fc="/Users/knepley/MacSoftware/bin/ccache gfortran" --with-shared-libraries [0]PETSC ERROR: #1 KSPSolve() line 847 in /PETSc3/petsc/petsc-dev/src/ksp/ksp/interface/itfunc.c [0]PETSC ERROR: #2 SNESSolve_NEWTONLS() line 224 in /PETSc3/petsc/petsc-dev/src/snes/impls/ls/ls.c [0]PETSC ERROR: #3 SNESSolve() line 3967 in /PETSc3/petsc/petsc-dev/src/snes/interface/snes.c [0]PETSC ERROR: #4 main() line 187 in /PETSc3/petsc/petsc-dev/src/snes/examples/tutorials/ex5.c [0]PETSC ERROR: PETSc Option Table entries: [0]PETSC ERROR: -ksp_error_if_not_converged [0]PETSC ERROR: -ksp_pc_side right [0]PETSC ERROR: -ksp_type cg [0]PETSC ERROR: -ksp_view [0]PETSC ERROR: -malloc_test [0]PETSC ERROR: ----------------End of Error Message -------send entire error message to petsc-ma...@mcs.anl.gov---------- So we are not getting an error Matt > > Fande, > > On Wed, Mar 8, 2017 at 9:33 AM, Barry Smith <bsm...@mcs.anl.gov> wrote: > >> >> Please tell us how you got this output. >> >> PETSc CG doesn't even implement right preconditioning. If you ask for >> it it should error out. CG supports no norm computation with left >> preconditioning. >> >> Barry >> >> > On Mar 8, 2017, at 10:26 AM, Kong, Fande <fande.k...@inl.gov> wrote: >> > >> > Hi All, >> > >> > The NONE norm type is supported only when CG is used with a right >> preconditioner. Any reason for this? >> > >> > >> > >> > 0 Nonlinear |R| = 1.732051e+00 >> > 0 Linear |R| = 0.000000e+00 >> > 1 Linear |R| = 0.000000e+00 >> > 2 Linear |R| = 0.000000e+00 >> > 3 Linear |R| = 0.000000e+00 >> > 4 Linear |R| = 0.000000e+00 >> > 5 Linear |R| = 0.000000e+00 >> > 6 Linear |R| = 0.000000e+00 >> > 1 Nonlinear |R| = 1.769225e-08 >> > 0 Linear |R| = 0.000000e+00 >> > 1 Linear |R| = 0.000000e+00 >> > 2 Linear |R| = 0.000000e+00 >> > 3 Linear |R| = 0.000000e+00 >> > 4 Linear |R| = 0.000000e+00 >> > 5 Linear |R| = 0.000000e+00 >> > 6 Linear |R| = 0.000000e+00 >> > 7 Linear |R| = 0.000000e+00 >> > 8 Linear |R| = 0.000000e+00 >> > 9 Linear |R| = 0.000000e+00 >> > 10 Linear |R| = 0.000000e+00 >> > 2 Nonlinear |R| = 0.000000e+00 >> > SNES Object: 1 MPI processes >> > type: newtonls >> > maximum iterations=50, maximum function evaluations=10000 >> > tolerances: relative=1e-08, absolute=1e-50, solution=1e-50 >> > total number of linear solver iterations=18 >> > total number of function evaluations=23 >> > norm schedule ALWAYS >> > SNESLineSearch Object: 1 MPI processes >> > type: bt >> > interpolation: cubic >> > alpha=1.000000e-04 >> > maxstep=1.000000e+08, minlambda=1.000000e-12 >> > tolerances: relative=1.000000e-08, absolute=1.000000e-15, >> lambda=1.000000e-08 >> > maximum iterations=40 >> > KSP Object: 1 MPI processes >> > type: cg >> > maximum iterations=10000, initial guess is zero >> > tolerances: relative=1e-05, absolute=1e-50, divergence=10000. >> > right preconditioning >> > using NONE norm type for convergence test >> > PC Object: 1 MPI processes >> > type: hypre >> > HYPRE BoomerAMG preconditioning >> > HYPRE BoomerAMG: Cycle type V >> > HYPRE BoomerAMG: Maximum number of levels 25 >> > HYPRE BoomerAMG: Maximum number of iterations PER hypre call 1 >> > HYPRE BoomerAMG: Convergence tolerance PER hypre call 0. >> > HYPRE BoomerAMG: Threshold for strong coupling 0.25 >> > HYPRE BoomerAMG: Interpolation truncation factor 0. >> > HYPRE BoomerAMG: Interpolation: max elements per row 0 >> > HYPRE BoomerAMG: Number of levels of aggressive coarsening 0 >> > HYPRE BoomerAMG: Number of paths for aggressive coarsening 1 >> > HYPRE BoomerAMG: Maximum row sums 0.9 >> > HYPRE BoomerAMG: Sweeps down 1 >> > HYPRE BoomerAMG: Sweeps up 1 >> > HYPRE BoomerAMG: Sweeps on coarse 1 >> > HYPRE BoomerAMG: Relax down symmetric-SOR/Jacobi >> > HYPRE BoomerAMG: Relax up symmetric-SOR/Jacobi >> > HYPRE BoomerAMG: Relax on coarse Gaussian-elimination >> > HYPRE BoomerAMG: Relax weight (all) 1. >> > HYPRE BoomerAMG: Outer relax weight (all) 1. >> > HYPRE BoomerAMG: Using CF-relaxation >> > HYPRE BoomerAMG: Not using more complex smoothers. >> > HYPRE BoomerAMG: Measure type local >> > HYPRE BoomerAMG: Coarsen type Falgout >> > HYPRE BoomerAMG: Interpolation type classical >> > linear system matrix followed by preconditioner matrix: >> > Mat Object: 1 MPI processes >> > type: mffd >> > rows=9, cols=9 >> > Matrix-free approximation: >> > err=1.49012e-08 (relative error in function evaluation) >> > Using wp compute h routine >> > Does not compute normU >> > Mat Object: () 1 MPI processes >> > type: seqaij >> > rows=9, cols=9 >> > total: nonzeros=49, allocated nonzeros=49 >> > total number of mallocs used during MatSetValues calls =0 >> > not using I-node routines >> > >> > Fande, >> > >> >> > -- 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