[petsc-users] Hypre BoomerAMG has slow convergence

Robert Annewandter robert.annewandter at opengosim.com
Tue Jul 4 11:59:42 CDT 2017


Hi all,


I'm working on a CPR-AMG Two-Stage preconditioner implemented as
multiplicative PCComposite with outer FGMRES, where the first PC is
Hypre AMG (PCGalerkin + KSPRichardson + PCHYPRE) and the second stage is
Block Jacobi with LU. The pde's describe two-phase subsurface flow, and
I kept the problem small at 8000 x 8000 dofs.

The first stage is hard-wired because of the PCGalerkin part and the
second stage Block Jacobi is configured via command line (with pflotran
prefix flow_):

  -flow_sub_1_pc_type bjacobi \
  -flow_sub_1_sub_pc_type lu \

With this configuration I see occasionally that Hypre struggles to
converge fast:


Step 16

    0 2r: 3.95E-03 2x: 0.00E+00 2u: 0.00E+00 ir: 2.53E-03 iu: 0.00E+00
rsn:   0
    Residual norms for flow_ solve.
    0 KSP unpreconditioned resid norm 3.945216988332e-03 true resid norm
3.945216988332e-03 ||r(i)||/||b|| 1.000000000000e+00
    Residual norms for flow_sub_0_galerkin_ solve.
    0 KSP preconditioned resid norm 2.495457360562e+08 true resid norm
9.213492769259e-01 ||r(i)||/||b|| 1.000000000000e+00
    1 KSP preconditioned resid norm 3.900401635809e+07 true resid norm
1.211813734614e-01 ||r(i)||/||b|| 1.315259874797e-01
    2 KSP preconditioned resid norm 7.264015944695e+06 true resid norm
2.127154159346e-02 ||r(i)||/||b|| 2.308738078618e-02
    3 KSP preconditioned resid norm 1.523934370189e+06 true resid norm
4.507204888834e-03 ||r(i)||/||b|| 4.891961172285e-03
    4 KSP preconditioned resid norm 3.456355485206e+05 true resid norm
1.017486337883e-03 ||r(i)||/||b|| 1.104343774250e-03
    5 KSP preconditioned resid norm 8.215494701640e+04 true resid norm
2.386758602821e-04 ||r(i)||/||b|| 2.590503582729e-04
    6 KSP preconditioned resid norm 2.006221595869e+04 true resid norm
5.806707975375e-05 ||r(i)||/||b|| 6.302395975986e-05
    7 KSP preconditioned resid norm 4.975749682114e+03 true resid norm
1.457831681999e-05 ||r(i)||/||b|| 1.582279075383e-05
    8 KSP preconditioned resid norm 1.245359749620e+03 true resid norm
3.746721600730e-06 ||r(i)||/||b|| 4.066559441204e-06
    9 KSP preconditioned resid norm 3.134373137075e+02 true resid norm
9.784665277082e-07 ||r(i)||/||b|| 1.061993048904e-06
   10 KSP preconditioned resid norm 7.917076489741e+01 true resid norm
2.582765351245e-07 ||r(i)||/||b|| 2.803242392356e-07
   11 KSP preconditioned resid norm 2.004702594193e+01 true resid norm
6.867609287185e-08 ||r(i)||/||b|| 7.453860831257e-08
    1 KSP unpreconditioned resid norm 3.022346103074e-11 true resid norm
3.022346103592e-11 ||r(i)||/||b|| 7.660785484121e-09
  1 2r: 2.87E-04 2x: 3.70E+09 2u: 3.36E+02 ir: 1.67E-04 iu: 2.19E+01
rsn: stol
Nonlinear flow_ solve converged due to CONVERGED_SNORM_RELATIVE iterations 1


Step 17

  0 2r: 3.85E-03 2x: 0.00E+00 2u: 0.00E+00 ir: 2.69E-03 iu: 0.00E+00
rsn:   0
    Residual norms for flow_ solve.
    0 KSP unpreconditioned resid norm 3.846677237838e-03 true resid norm
3.846677237838e-03 ||r(i)||/||b|| 1.000000000000e+00
    Residual norms for flow_sub_0_galerkin_ solve.
    0 KSP preconditioned resid norm 8.359592959751e+07 true resid norm
8.919381920269e-01 ||r(i)||/||b|| 1.000000000000e+00
    1 KSP preconditioned resid norm 2.046474217608e+07 true resid norm
1.356172589724e+00 ||r(i)||/||b|| 1.520478214574e+00
    2 KSP preconditioned resid norm 5.534610937223e+06 true resid norm
1.361527715124e+00 ||r(i)||/||b|| 1.526482134406e+00
    3 KSP preconditioned resid norm 1.642592089665e+06 true resid norm
1.359990274368e+00 ||r(i)||/||b|| 1.524758426677e+00
    4 KSP preconditioned resid norm 6.869446528993e+05 true resid norm
1.357740694885e+00 ||r(i)||/||b|| 1.522236301823e+00
    5 KSP preconditioned resid norm 5.245968674991e+05 true resid norm
1.355364470917e+00 ||r(i)||/||b|| 1.519572189007e+00
    6 KSP preconditioned resid norm 5.042030663187e+05 true resid norm
1.352962944308e+00 ||r(i)||/||b|| 1.516879708036e+00
    7 KSP preconditioned resid norm 5.007302249221e+05 true resid norm
1.350558656878e+00 ||r(i)||/||b|| 1.514184131760e+00
    8 KSP preconditioned resid norm 4.994105316949e+05 true resid norm
1.348156961110e+00 ||r(i)||/||b|| 1.511491461137e+00
    9 KSP preconditioned resid norm 4.984373051647e+05 true resid norm
1.345759135434e+00 ||r(i)||/||b|| 1.508803129481e+00
   10 KSP preconditioned resid norm 4.975323739321e+05 true resid norm
1.343365479502e+00 ||r(i)||/||b|| 1.506119472750e+00
   11 KSP preconditioned resid norm 4.966432959339e+05 true resid norm
1.340976058673e+00 ||r(i)||/||b|| 1.503440564224e+00
[...]
  193 KSP preconditioned resid norm 3.591931201817e+05 true resid norm
9.698521332569e-01 ||r(i)||/||b|| 1.087353520599e+00
  194 KSP preconditioned resid norm 3.585542278288e+05 true resid norm
9.681270691497e-01 ||r(i)||/||b|| 1.085419458213e+00
  195 KSP preconditioned resid norm 3.579164717745e+05 true resid norm
9.664050733935e-01 ||r(i)||/||b|| 1.083488835922e+00
  196 KSP preconditioned resid norm 3.572798501551e+05 true resid norm
9.646861405301e-01 ||r(i)||/||b|| 1.081561647605e+00
  197 KSP preconditioned resid norm 3.566443608646e+05 true resid norm
9.629702651108e-01 ||r(i)||/||b|| 1.079637887153e+00
  198 KSP preconditioned resid norm 3.560100018703e+05 true resid norm
9.612574416991e-01 ||r(i)||/||b|| 1.077717548471e+00
  199 KSP preconditioned resid norm 3.553767713002e+05 true resid norm
9.595476648643e-01 ||r(i)||/||b|| 1.075800625471e+00
  200 KSP preconditioned resid norm 3.547446669197e+05 true resid norm
9.578409291897e-01 ||r(i)||/||b|| 1.073887112080e+00
    1 KSP unpreconditioned resid norm 3.816569407795e-11 true resid norm
3.816569407353e-11 ||r(i)||/||b|| 9.921730291825e-09
  1 2r: 2.74E-02 2x: 3.70E+09 2u: 1.23E+02 ir: 1.99E-02 iu: 2.71E+01
rsn: stol
Nonlinear flow_ solve converged due to CONVERGED_SNORM_RELATIVE iterations 1

Step 18

  0 2r: 2.73E-02 2x: 0.00E+00 2u: 0.00E+00 ir: 2.02E-02 iu: 0.00E+00
rsn:   0
    Residual norms for flow_ solve.
    0 KSP unpreconditioned resid norm 2.734891161446e-02 true resid norm
2.734891161446e-02 ||r(i)||/||b|| 1.000000000000e+00
    Residual norms for flow_sub_0_galerkin_ solve.
    0 KSP preconditioned resid norm 3.550345478098e+07 true resid norm
1.048585361984e+00 ||r(i)||/||b|| 1.000000000000e+00
    1 KSP preconditioned resid norm 6.139218831613e+06 true resid norm
1.797822962324e-02 ||r(i)||/||b|| 1.714522276873e-02
    2 KSP preconditioned resid norm 1.301871956838e+06 true resid norm
3.761355992926e-03 ||r(i)||/||b|| 3.587076578878e-03
    3 KSP preconditioned resid norm 3.070518418113e+05 true resid norm
9.283056182563e-04 ||r(i)||/||b|| 8.852933217570e-04
    4 KSP preconditioned resid norm 7.639640178912e+04 true resid norm
2.348078927331e-04 ||r(i)||/||b|| 2.239282572941e-04
    5 KSP preconditioned resid norm 1.953032767966e+04 true resid norm
5.930230662989e-05 ||r(i)||/||b|| 5.655458180124e-05
    6 KSP preconditioned resid norm 5.066937883132e+03 true resid norm
1.497534370201e-05 ||r(i)||/||b|| 1.428147315892e-05
    7 KSP preconditioned resid norm 1.326441080568e+03 true resid norm
3.793872760594e-06 ||r(i)||/||b|| 3.618086708188e-06
    8 KSP preconditioned resid norm 3.494353490063e+02 true resid norm
9.659536247849e-07 ||r(i)||/||b|| 9.211969380896e-07
    9 KSP preconditioned resid norm 9.251497983280e+01 true resid norm
2.472922526467e-07 ||r(i)||/||b|| 2.358341644011e-07
   10 KSP preconditioned resid norm 2.459917675189e+01 true resid norm
6.364691902290e-08 ||r(i)||/||b|| 6.069789006257e-08
   11 KSP preconditioned resid norm 6.566117552226e+00 true resid norm
1.646205416458e-08 ||r(i)||/||b|| 1.569929808426e-08
   12 KSP preconditioned resid norm 1.758927386308e+00 true resid norm
4.277033775892e-09 ||r(i)||/||b|| 4.078860845245e-09
    1 KSP unpreconditioned resid norm 2.831146511164e-10 true resid norm
2.831146511142e-10 ||r(i)||/||b|| 1.035195312725e-08
  1 2r: 1.31E-02 2x: 3.70E+09 2u: 3.66E+02 ir: 9.77E-03 iu: 6.03E+01
rsn: stol
Nonlinear flow_ solve converged due to CONVERGED_SNORM_RELATIVE iterations 1



SNES_view:


SNES Object: (flow_) 2 MPI processes
  type: newtonls
  maximum iterations=8, maximum function evaluations=10000
  tolerances: relative=1e-05, absolute=1e-05, solution=1e-05
  total number of linear solver iterations=1
  total number of function evaluations=2
  norm schedule ALWAYS
  SNESLineSearch Object: (flow_) 2 MPI processes
    type: basic
    maxstep=1.000000e+08, minlambda=1.000000e-05
    tolerances: relative=1.000000e-08, absolute=1.000000e-15,
lambda=1.000000e-08
    maximum iterations=40
    using user-defined precheck step
  KSP Object: (flow_) 2 MPI processes
    type: fgmres
      GMRES: restart=30, using Classical (unmodified) Gram-Schmidt
Orthogonalization with no iterative refinement
      GMRES: happy breakdown tolerance 1e-30
    maximum iterations=200, initial guess is zero
    tolerances:  relative=1e-07, absolute=1e-50, divergence=10000.
    right preconditioning
    using UNPRECONDITIONED norm type for convergence test
  PC Object: (flow_) 2 MPI processes
    type: composite
    Composite PC type - MULTIPLICATIVE
    PCs on composite preconditioner follow
    ---------------------------------
      PC Object: (flow_sub_0_) 2 MPI processes
        type: galerkin
        Galerkin PC
        KSP on Galerkin follow
        ---------------------------------
        KSP Object: (flow_sub_0_galerkin_) 2 MPI processes
          type: richardson
            Richardson: damping factor=1.
          maximum iterations=200, initial guess is zero
          tolerances:  relative=1e-07, absolute=1e-50, divergence=10000.
          left preconditioning
          using PRECONDITIONED norm type for convergence test
        PC Object: (flow_sub_0_galerkin_) 2 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 = precond matrix:
          Mat Object: 2 MPI processes
            type: mpiaij
            rows=8000, cols=8000
            total: nonzeros=53600, allocated nonzeros=53600
            total number of mallocs used during MatSetValues calls =0
              not using I-node (on process 0) routines
        linear system matrix = precond matrix:
        Mat Object: (flow_) 2 MPI processes
          type: mpibaij
          rows=24000, cols=24000, bs=3
          total: nonzeros=482400, allocated nonzeros=482400
          total number of mallocs used during MatSetValues calls =0
      PC Object: (flow_sub_1_) 2 MPI processes
        type: bjacobi
          block Jacobi: number of blocks = 2
          Local solve is same for all blocks, in the following KSP and
PC objects:
        KSP Object: (flow_sub_1_sub_) 1 MPI processes
          type: preonly
          maximum iterations=10000, initial guess is zero
          tolerances:  relative=1e-05, absolute=1e-50, divergence=10000.
          left preconditioning
          using NONE norm type for convergence test
        PC Object: (flow_sub_1_sub_) 1 MPI processes
          type: lu
            out-of-place factorization
            tolerance for zero pivot 2.22045e-14
            matrix ordering: nd
            factor fill ratio given 5., needed 18.3108
              Factored matrix follows:
                Mat Object: 1 MPI processes
                  type: seqbaij
                  rows=12000, cols=12000, bs=3
                  package used to perform factorization: petsc
                  total: nonzeros=4350654, allocated nonzeros=4350654
                  total number of mallocs used during MatSetValues calls =0
                      block size is 3
          linear system matrix = precond matrix:
          Mat Object: (flow_) 1 MPI processes
            type: seqbaij
            rows=12000, cols=12000, bs=3
            total: nonzeros=237600, allocated nonzeros=237600
            total number of mallocs used during MatSetValues calls =0
                block size is 3
        linear system matrix = precond matrix:
        Mat Object: (flow_) 2 MPI processes
          type: mpibaij
          rows=24000, cols=24000, bs=3
          total: nonzeros=482400, allocated nonzeros=482400
          total number of mallocs used during MatSetValues calls =0
    ---------------------------------
    linear system matrix = precond matrix:
    Mat Object: (flow_) 2 MPI processes
      type: mpibaij
      rows=24000, cols=24000, bs=3
      total: nonzeros=482400, allocated nonzeros=482400
      total number of mallocs used during MatSetValues calls =0



Is there a way to improve on the AMG part? Do I have to adjust the
tolerances (make the inner tighter)? Which Hypre AMG parameters are
worth tuning?  This problem occurs for 1 MPI process as well, and
solving the problem in Standard PFLOTRAN (i.e. Block Jacobi + ILU) is
without any issue.

Grateful for any help!
Robert



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