[petsc-users] Dose Petsc has DMPlex example

Hoang Giang Bui hgbk2008 at gmail.com
Sun Jul 3 03:06:38 CDT 2016


Hi Matt

I tried to run ex62 with 1 proc (petsc 3.7.2), but it all produces zero

The output is:
hbui at bermuda:~/workspace/petsc/snes$ es$ ./ex62 run_type full -bc_type
dirichlet -refinement_limit 0.00625 -interpolate 1 -snes_monitor_short
-snes_converged_reason -snes_view -ksp_type fgmres -ksp_gmres_restart 100
-ksp_rtol 1.0e-9 -ksp_monitor_short -pc_type fieldsplit -pc_fieldsplit_type
schur -pc_fieldsplit_schur_factorization_type full
-fieldsplit_velocity_ksp_type gmres -fieldsplit_velocity_pc_type lu
-fieldsplit_pressure_ksp_rtol 1e-10 -fieldsplit_pressure_pc_type jacobi
  0 SNES Function norm 0.265165
    0 KSP Residual norm 0.265165
Nonlinear solve did not converge due to DIVERGED_LINEAR_SOLVE iterations 0
SNES Object: 1 MPI processes
  type: newtonls
  maximum iterations=50, maximum function evaluations=10000
  tolerances: relative=1e-08, absolute=1e-50, solution=1e-08
  total number of linear solver iterations=0
  total number of function evaluations=1
  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: fgmres
      GMRES: restart=100, using Classical (unmodified) Gram-Schmidt
Orthogonalization with no iterative refinement
      GMRES: happy breakdown tolerance 1e-30
    maximum iterations=10000, initial guess is zero
    tolerances:  relative=1e-09, absolute=1e-50, divergence=10000.
    right preconditioning
    using UNPRECONDITIONED norm type for convergence test
  PC Object:   1 MPI processes
    type: fieldsplit
      FieldSplit with Schur preconditioner, factorization FULL
      Preconditioner for the Schur complement formed from A11
      Split info:
      Split number 0 Defined by IS
      Split number 1 Defined by IS
      KSP solver for A00 block
        KSP Object:        (fieldsplit_velocity_)         1 MPI processes
          type: gmres
            GMRES: restart=30, using Classical (unmodified) Gram-Schmidt
Orthogonalization with no iterative refinement
            GMRES: happy breakdown tolerance 1e-30
          maximum iterations=10000, initial guess is zero
          tolerances:  relative=1e-05, absolute=1e-50, divergence=10000.
          left preconditioning
          using PRECONDITIONED norm type for convergence test
        PC Object:        (fieldsplit_velocity_)         1 MPI processes
          type: lu
            LU: out-of-place factorization
            tolerance for zero pivot 2.22045e-14
            matrix ordering: nd
            factor fill ratio given 5., needed 1.
              Factored matrix follows:
                Mat Object:                 1 MPI processes
                  type: seqaij
                  rows=512, cols=512, bs=2
                  package used to perform factorization: petsc
                  total: nonzeros=1024, allocated nonzeros=1024
                  total number of mallocs used during MatSetValues calls =0
                    using I-node routines: found 256 nodes, limit used is 5
          linear system matrix = precond matrix:
          Mat Object:          (fieldsplit_velocity_)           1 MPI
processes
            type: seqaij
            rows=512, cols=512, bs=2
            total: nonzeros=1024, allocated nonzeros=1024
            total number of mallocs used during MatSetValues calls =0
              using I-node routines: found 256 nodes, limit used is 5
      KSP solver for S = A11 - A10 inv(A00) A01
        KSP Object:        (fieldsplit_pressure_)         1 MPI processes
          type: gmres
            GMRES: restart=30, using Classical (unmodified) Gram-Schmidt
Orthogonalization with no iterative refinement
            GMRES: happy breakdown tolerance 1e-30
          maximum iterations=10000, initial guess is zero
          tolerances:  relative=1e-10, absolute=1e-50, divergence=10000.
          left preconditioning
          using PRECONDITIONED norm type for convergence test
        PC Object:        (fieldsplit_pressure_)         1 MPI processes
          type: jacobi
          linear system matrix followed by preconditioner matrix:
          Mat Object:          (fieldsplit_pressure_)           1 MPI
processes
            type: schurcomplement
            rows=256, cols=256
              has attached null space
              Schur complement A11 - A10 inv(A00) A01
              A11
                Mat Object:
(fieldsplit_pressure_)                 1 MPI processes
                  type: seqaij
                  rows=256, cols=256
                  total: nonzeros=256, allocated nonzeros=256
                  total number of mallocs used during MatSetValues calls =0
                    has attached null space
                    not using I-node routines
              A10
                Mat Object:                 1 MPI processes
                  type: seqaij
                  rows=256, cols=512
                  total: nonzeros=512, allocated nonzeros=512
                  total number of mallocs used during MatSetValues calls =0
                    not using I-node routines
              KSP of A00
                KSP Object:
(fieldsplit_velocity_)                 1 MPI processes
                  type: gmres
                    GMRES: restart=30, using Classical (unmodified)
Gram-Schmidt Orthogonalization with no iterative refinement
                    GMRES: happy breakdown tolerance 1e-30
                  maximum iterations=10000, initial guess is zero
                  tolerances:  relative=1e-05, absolute=1e-50,
divergence=10000.
                  left preconditioning
                  using PRECONDITIONED norm type for convergence test
                PC Object:
(fieldsplit_velocity_)                 1 MPI processes
                  type: lu
                    LU: out-of-place factorization
                    tolerance for zero pivot 2.22045e-14
                    matrix ordering: nd
                    factor fill ratio given 5., needed 1.
                      Factored matrix follows:
                        Mat Object:                         1 MPI processes
                          type: seqaij
                          rows=512, cols=512, bs=2
                          package used to perform factorization: petsc
                          total: nonzeros=1024, allocated nonzeros=1024
                          total number of mallocs used during MatSetValues
calls =0
                            using I-node routines: found 256 nodes, limit
used is 5
                  linear system matrix = precond matrix:
                  Mat Object:
(fieldsplit_velocity_)                   1 MPI processes
                    type: seqaij
                    rows=512, cols=512, bs=2
                    total: nonzeros=1024, allocated nonzeros=1024
                    total number of mallocs used during MatSetValues calls
=0
                      using I-node routines: found 256 nodes, limit used is
5
              A01
                Mat Object:                 1 MPI processes
                  type: seqaij
                  rows=512, cols=256, rbs=2, cbs = 1
                  total: nonzeros=512, allocated nonzeros=512
                  total number of mallocs used during MatSetValues calls =0
                    using I-node routines: found 256 nodes, limit used is 5
          Mat Object:          (fieldsplit_pressure_)           1 MPI
processes
            type: seqaij
            rows=256, cols=256
            total: nonzeros=256, allocated nonzeros=256
            total number of mallocs used during MatSetValues calls =0
              has attached null space
              not using I-node routines
    linear system matrix = precond matrix:
    Mat Object:     1 MPI processes
      type: seqaij
      rows=768, cols=768
      total: nonzeros=2304, allocated nonzeros=2304
      total number of mallocs used during MatSetValues calls =0
        has attached null space
        using I-node routines: found 256 nodes, limit used is 5
Number of SNES iterations = 0
L_2 Error: 1.01 [0.929, 0.407]
Solution
Vec Object: 1 MPI processes
  type: seq
0.
0.
....

Am I doing something wrong?

Giang


Giang

On Tue, May 3, 2016 at 4:44 AM, Matthew Knepley <knepley at gmail.com> wrote:

> On Mon, May 2, 2016 at 8:29 PM, ztdepyahoo at 163.com <ztdepyahoo at 163.com>
> wrote:
>
>> Dear professor:
>>       I want to write a parallel 3D CFD code based on unstructred grid,
>> does Petsc has DMPlex examples to start with.
>>
>
> SNES ex62 is an unstructured grid Stokes problem discretized with
> low-order finite elements.
>
> Of course, all the different possible choices will impact the design.
>
>    Matt
>
>
>> Regards
>>
>
>
>
> --
> 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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