[petsc-users] CG with right preconditioning supports NONE norm type only

[Jed Brown]

Looks fine to me.  Thanks.

Barry Smith <bsmith at mcs.anl.gov> writes:

>    A proposed fix https://bitbucket.org/petsc/petsc/pull-requests/645/do-not-assume-that-all-ksp-methods-support
>
>    Needs Jed's approval.
>
>    Barry
>
>
>   
>> On Mar 8, 2017, at 10:33 AM, Barry Smith <bsmith at 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.kong at 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,
>>> 
>> 
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