[petsc-users] KSPsolver

[Jin, Shuangshuang]

Hi, by running mpiexec -n 2 ./ex12 -ksp_view, I got:

[d3m956 at olympus ksp]$ mpiexec -n 2 ./ex12 -ksp_view
0, 56
0, 56
KSP Object: 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: 1 MPI processes
  type: ourjacobi
  linear system matrix = precond matrix:
KSP Object: 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: 1 MPI processes
  type: ourjacobi
  linear system matrix = precond matrix:
  Matrix Object:   1 MPI processes
    type: seqaij
    rows=56, cols=56
    total: nonzeros=250, allocated nonzeros=280
    total number of mallocs used during MatSetValues calls =0
      not using I-node routines
Norm of error 2.10144e-06 iterations 14
  Matrix Object:   1 MPI processes
    type: seqaij
    rows=56, cols=56
    total: nonzeros=250, allocated nonzeros=280
    total number of mallocs used during MatSetValues calls =0
      not using I-node routines
Norm of error 2.10144e-06 iterations 14

Thanks,
Shuangshuang

From: petsc-users-bounces at mcs.anl.gov [mailto:petsc-users-bounces at mcs.anl.gov] On Behalf Of Hong Zhang
Sent: Tuesday, April 16, 2013 11:26 AM
To: PETSc users list
Subject: Re: [petsc-users] KSPsolver

What do you get by running
mpiexec -n 2 ./ex12 -ksp_view

I get
mpiexec -n 2 ./ex12 -ksp_view
KSP Object: 2 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
  GMRES: restart=30, using Classical (unmodified) Gram-Schmidt Orthogonalization with no iterative refinement
  GMRES: happy breakdown tolerance 1e-30
PC Object: 2 MPI processes
  type: ourjacobi
  linear system matrix = precond matrix:
  Matrix Object:   2 MPI processes
    type: mpiaij
    rows=56, cols=56
    total: nonzeros=250, allocated nonzeros=560
    total number of mallocs used during MatSetValues calls =0
      not using I-node (on process 0) routines
Norm of error 2.10144e-06 iterations 14

Hong


On Tue, Apr 16, 2013 at 1:17 PM, Jin, Shuangshuang <Shuangshuang.Jin at pnnl.gov<mailto:Shuangshuang.Jin at pnnl.gov>> wrote:
Hello, everyone, I'm trying to run the following example: http://www.mcs.anl.gov/petsc/petsc-current/src/ksp/ksp/examples/tutorials/ex12.c.html

It is said that this example solves a linear system in parallel with KSP.

However, when I ran it on my clusters, I always got the same copy running multiple times. I printed the Istart and Iend numbers right after the MatGetOwnershipRange, and noticed that the index on each processor are all the same, which is [0, 56].

The following is the printout from the runs:

[d3m956 at olympus ksp]$ mpiexec -n 1 ./ex12
0, 56
Norm of error 2.10144e-06 iterations 14
[d3m956 at olympus ksp]$ mpiexec -n 2 ./ex12
0, 56
0, 56
Norm of error 2.10144e-06 iterations 14
Norm of error 2.10144e-06 iterations 14
[d3m956 at olympus ksp]$ mpiexec -n 4 ./ex12
0, 56
0, 56
0, 56
0, 56
Norm of error 2.10144e-06 iterations 14
Norm of error 2.10144e-06 iterations 14
Norm of error 2.10144e-06 iterations 14
Norm of error 2.10144e-06 iterations 14

Can anyone explain to me why I ran into this issue? Anything I missed?

Thanks,
Shuangshuang



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