[petsc-users] Troubles updating my code from PETSc-3.4 to 3.5 Using MUMPS for KSPSolve()
Marc MEDALE
marc.medale at univ-amu.fr
Thu Dec 11 10:07:51 CST 2014
Dear Matt,
the output files obtained with PETSc-3.4p4 and 3.5p1 versions using the following command line:
-ksp_type preonly -pc_type lu -pc_factor_mat_solver_package mumps -mat_mumps_icntl_8 0 -ksp_monitor -ksp_view
are attached below. If skipping flops and memory usage per core, a diff between the two output files reduces to:
diff Output_3.4p4.txt Output_3.5p1.txt
14c14
< Matrix Object: 64 MPI processes
---
> Mat Object: 64 MPI processes
18c18
< total: nonzeros=481059588, allocated nonzeros=481059588
---
> total: nonzeros=4.8106e+08, allocated nonzeros=4.8106e+08
457c457
< INFOG(10) (total integer space store the matrix factors after factorization): 26149876
---
> INFOG(10) (total integer space store the matrix factors after factorization): 26136333
461c461
< INFOG(14) (number of memory compress after factorization): 54
---
> INFOG(14) (number of memory compress after factorization): 48
468,469c468,469
< INFOG(21) (size in MB of memory effectively used during factorization - value on the most memory consuming processor): 338
< INFOG(22) (size in MB of memory effectively used during factorization - sum over all processors): 19782
---
> INFOG(21) (size in MB of memory effectively used during factorization - value on the most memory consuming processor): 334
> INFOG(22) (size in MB of memory effectively used during factorization - sum over all processors): 19779
472a473,478
> INFOG(28) (after factorization: number of null pivots encountered): 0
> INFOG(29) (after factorization: effective number of entries in the factors (sum over all processors)): 470143172
> INFOG(30, 31) (after solution: size in Mbytes of memory used during solution phase): 202, 10547
> INFOG(32) (after analysis: type of analysis done): 1
> INFOG(33) (value used for ICNTL(8)): 0
> INFOG(34) (exponent of the determinant if determinant is requested): 0
474c480
< Matrix Object: 64 MPI processes
---
> Mat Object: 64 MPI processes
477c483
< total: nonzeros=63720324, allocated nonzeros=63720324
---
> total: nonzeros=6.37203e+07, allocated nonzeros=6.37203e+07
481c487
< Norme de U 1 7.37266E-02, L 1 1.00000E+00
---
> Norme de U 1 1.61172E-02, L 1 1.00000E+00
483c489
< Temps total d execution : 198.373291969299
---
> Temps total d execution : 216.934082031250
Which does not reveal any striking differences, except in the L2 norm of the solution vectors.
I need assistance to help me to overcome this quite bizarre behavior.
Thank you.
Marc MEDALE
=========================================================
Université Aix-Marseille, Polytech'Marseille, Dépt Mécanique Energétique
Laboratoire IUSTI, UMR 7343 CNRS-Université Aix-Marseille
Technopole de Chateau-Gombert, 5 rue Enrico Fermi
13453 MARSEILLE, Cedex 13, FRANCE
---------------------------------------------------------------------------------------------------
Tel : +33 (0)4.91.10.69.14 ou 38
Fax : +33 (0)4.91.10.69.69
e-mail : marc.medale at univ-amu.fr
=========================================================
Le 11 déc. 2014 à 11:43, Matthew Knepley <knepley at gmail.com> a écrit :
> On Thu, Dec 11, 2014 at 4:38 AM, Marc MEDALE <marc.medale at univ-amu.fr> wrote:
> Dear PETSC Users,
>
> I have just updated to PETSc-3.5 my research code that uses PETSc for a while but I'm facing an astonishing difference between PETSc-3.4 to 3.5 versions when solving a very ill conditioned algebraic system with MUMPS (4.10.0 in both cases).
>
> The only differences that arise in my fortran source code are the following:
> Loma1-medale% diff ../version_3.5/solvEFL_MAN_SBIF.F ../version_3.4/solvEFL_MAN_SBIF.F
> 336,337d335
> < CALL MatSetOption(MATGLOB,MAT_KEEP_NONZERO_PATTERN,
> < & PETSC_TRUE,IER)
> 749,750c747,748
> < CALL KSPSetTolerances(KSP1,TOL,PETSC_DEFAULT_REAL,
> < & PETSC_DEFAULT_REAL,PETSC_DEFAULT_INTEGER,IER)
> ---
> > CALL KSPSetTolerances(KSP1,TOL,PETSC_DEFAULT_DOUBLE_PRECISION,
> > & PETSC_DEFAULT_DOUBLE_PRECISION,PETSC_DEFAULT_INTEGER,IER)
> 909c907,908
> < CALL KSPSetOperators(KSP1,MATGLOB,MATGLOB,IER)
> ---
> > CALL KSPSetOperators(KSP1,MATGLOB,MATGLOB,
> > & SAME_NONZERO_PATTERN,IER)
>
> When I run the corresponding program versions on 128 cores of our cluster with the same input data and the following command line arguments:
> -ksp_type preonly -pc_type lu -pc_factor_mat_solver_package mumps -mat_mumps_icntl_8 0
>
> I get the following outputs:
> a) with PETSc-3.4p4:
> L2 norm of solution vector: 7.39640E-02,
>
> b) with PETSc-3.5p1:
> L2 norm of solution vector: 1.61325E-02
>
> Do I have change something else in updating my code based on KSP from PETSc-3.4 to 3.5 versions?
> Do any default values in the PETSc-MUMPS interface have been changed from PETSc-3.4 to 3.5?
> Any hints or suggestions are welcome to help me to recover the right results (obtained with PETSc-3.4).
>
> Send the output from -ksp_monitor -ksp_view for both runs. I am guessing that a MUMPS default changed between versions.
>
> Thanks,
>
> Matt
>
> Thank you very much.
>
> Marc MEDALE.
>
>
>
> --
> 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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