[petsc-users] use Superlu as ilu preconditioner

[Hong Zhang]

Ping :
I tested similar calling procedure using
petsc-dev/src/ksp/ksp/examples/tutorials/ex5.c
successfully.

Try following:
1) switch to petsc-dev. See
http://www.mcs.anl.gov/petsc/petsc-as/developers/index.html on how to
get it.
2) send us a short and stand-alone code that reproduce the error. We
can investigate it.

Hong

> Dear Hong,
>
> thank you very much for your time. Can you tell me when should
>  KSPSetFromOptions(ksp) be called?
> well, libMesh has a class called "petsc_linear_solver", in its original code
> KSPSetFromOptions(ksp) is called while the object is created. I couldn't get
> any output, when I run the program with the option
>
>   -pc_type ilu -pc_factor_mat_solver_package superlu
> -mat_superlu_ilu_droptol 0.1 -ksp_view
>
> The actual solve() function of the "petsc_linear_solver" contains the
> similar code as in the ex2.c
> ...
>    ierr = KSPSetOperators(_ksp, matrix->mat(), precond->mat(),
>                                             this->same_preconditioner ?
> SAME_PRECONDITIONER : DIFFERENT_NONZERO_PATTERN);
>    CHKERRABORT(libMesh::COMM_WORLD,ierr);
>
>  // Set the tolerances for the iterative solver.  Use the user-supplied
>  // tolerance for the relative residual & leave the others at default
> values.
>  ierr = KSPSetTolerances (_ksp, tol, PETSC_DEFAULT, PETSC_DEFAULT, max_its);
>  CHKERRABORT(libMesh::COMM_WORLD,ierr);
>
>  ierr = KSPSetFromOptions (_ksp); <--------------  I added these two lines,
>  CHKERRABORT(libMesh::COMM_WORLD,ierr); <--------------  then I got proper
> output.
>
>  // Solve the linear system
>  ierr = KSPSolve (_ksp, rhs->vec(), solution->vec());
>  CHKERRABORT(libMesh::COMM_WORLD,ierr);
> ....
>
> The problem is that I have to solve a multiple frequency system, and for
> each frequency I have several RHS. The same ksp context is used to solve the
> systems repeatedly. I always call KSPSetOperators() with the option
> DIFFERENT_NONZERO_PATTERN for the first RHS and SAME_PRECONDITIONER for the
> rest, since the system matrix remains the same.  For the first frequency,
> everything is fine, both DIFFERENT_NONZERO_PATTERN and SAME_PRECONDITIONER
> options. I got following output from the -ksp_view.
> ...
> PC Object:
>  type: ilu
>    ILU: out-of-place factorization
>    0 levels of fill
>    tolerance for zero pivot 1e-12
>    using diagonal shift to prevent zero pivot
>    matrix ordering: natural
>    factor fill ratio given 0, needed 0
>      Factored matrix follows:
>        Matrix Object:
>          type=seqaij, rows=2883, cols=2883
>          package used to perform factorization: superlu <----------------
> superlu is properly set
> ....
>
> but when the second frequency comes up, KSPSetOperators() is called again
> with DIFFERENT_NONZERO_PATTERN option for the first RHS. the command line
> option doesn't seem to work anymore.
> ...
> PC Object:
>  type: ilu
>    ILU: out-of-place factorization
>    0 levels of fill
>    tolerance for zero pivot 1e-12
>    using diagonal shift to prevent zero pivot
>    matrix ordering: natural
>    factor fill ratio given 1, needed 1
>      Factored matrix follows:
>        Matrix Object:
>          type=seqaij, rows=2883, cols=2883
>          package used to perform factorization: petsc <------------ not
> superlu anymore
> ...
>
> and then for the second RHS, when it calls KSPSetOperators(ksp) in the
> solve() routine, petsc throws the following error message.
>
> [0]PETSC ERROR: --------------------- Error Message
> ------------------------------------
> [0]PETSC ERROR: Object is in wrong state!
> [0]PETSC ERROR: Cannot change solver matrix package after PC has been setup
> or used!
> [0]PETSC ERROR:
> ------------------------------------------------------------------------
> [0]PETSC ERROR: Petsc Release Version 3.1.0, Patch 8, Thu Mar 17 13:37:48
> CDT 2011
> [0]PETSC ERROR: See docs/changes/index.html for recent updates.
> [0]PETSC ERROR: See docs/faq.html for hints about trouble shooting.
> [0]PETSC ERROR: See docs/index.html for manual pages.
> [0]PETSC ERROR:
> ------------------------------------------------------------------------
> [0]PETSC ERROR: ./PLTMainTest.opt on a linux-gnu named abe-vm by mubpr Wed
> Jul 27 19:41:22 2011
> [0]PETSC ERROR: Libraries linked from
> /home/mubpr/libs/petsc/linux-gnu-acml-shared-opt/lib
> [0]PETSC ERROR: Configure run at Tue Jul 26 22:09:39 2011
> [0]PETSC ERROR: Configure options
> --with-blas-lapack-lib=/home/mubpr/libs/acml/gfortran64_mp/lib/libacml_mp.so
> --with-blas-lapack-include=/home/mubpr/libs/acml/gfortran64_mp/include
> --with-scalar-type=complex --with-clanguage=c++
> --with-mpi-dir=/home/mubpr/libs/mpich2 --download-superlu=yes
> --with-superlu=1 --download-parmetis=yes --with-parmetis=1
> --download-superlu_dist=yes --with-superlu_dist=1 --download-mumps=yes
> --with-mumps=1 --download-blacs=yes --with-blacs=1 --download-scalapack=yes
> --with-scalapack=1 --download-spooles=yes --with-spooles=1
> --download-umfpack=yes --with-umfpack=1 --with-debugging=no --with-shared=1
> [0]PETSC ERROR:
> ------------------------------------------------------------------------
> [0]PETSC ERROR: PCFactorSetMatSolverPackage_Factor() line 183 in
> src/ksp/pc/impls/factor/factimpl.c
> [0]PETSC ERROR: PCFactorSetMatSolverPackage() line 276 in
> src/ksp/pc/impls/factor/factor.c
> [0]PETSC ERROR: PCSetFromOptions_Factor() line 275 in
> src/ksp/pc/impls/factor/factimpl.c
> [0]PETSC ERROR: PCSetFromOptions_ILU() line 112 in
> src/ksp/pc/impls/factor/ilu/ilu.c
> [0]PETSC ERROR: PCSetFromOptions() line 185 in src/ksp/pc/interface/pcset.c
> [0]PETSC ERROR: KSPSetFromOptions() line 323 in src/ksp/ksp/interface/itcl.c
> [0]PETSC ERROR: User provided function() line 696 in
> "unknowndirectory/"src/solvers/petsc_linear_solver.C
>
> Any idea what the problem may be? I would be very grateful, if you can give
> me any hint. thanks alot
>
> best regards
> Ping
>
>
>
> Am 27.07.2011 04:13, schrieb Hong Zhang:
>>
>> Did you call KSPSetFromOptions(ksp)?
>> Run your code with '-options_table' to dump list of options inputted
>> or '-options_left' to dump list of unused options.
>>
>> I tested with petsc-3.1/src/ksp/ksp/examples/tutorials/ex2.c:
>> ./ex2
>> ...
>>             SuperLU run parameters:
>>             ...
>>               ILU_DropTol: 0.1
>>               ILU_FillTol: 0.01
>>               ILU_FillFactor: 10
>>               ILU_DropRule: 9
>>               ILU_Norm: 2
>>               ILU_MILU: 2
>>
>> Hong
>>
>> On Tue, Jul 26, 2011 at 3:53 PM, Ping Rong<ping.rong at tuhh.de>  wrote:
>>>
>>> Dear developers,
>>>
>>> I have compiled petsc-3.1-p8 for a while. Now I would like to use superlu
>>> as
>>> an ilu preconditioner, since it offers the drop tolerance option. I have
>>> read in a thread
>>>
>>> (https://lists.mcs.anl.gov/mailman/htdig/petsc-users/2010-December/007439.html)
>>> that one can run the code with option
>>>
>>> -pc_type ilu -pc_factor_mat_solver_package superlu
>>> -mat_superlu_ilu_droptol
>>> <>
>>>
>>> to setup the ilu preconditioner. I also use the option "-help |grep
>>> superlu"
>>> to check the settings. However, no matter how I change the value of
>>> -mat_superlu_ilu_droptol, I always got the same result
>>> ...
>>>  -mat_superlu_lwork<0>: size of work array in bytes used by factorization
>>> (None)
>>>  -mat_superlu_ilu_droptol<0.0001>: ILU_DropTol (None)
>>>  -mat_superlu_ilu_filltol<0.01>: ILU_FillTol (None)
>>> ...
>>> I dont know whether I understand it correctly. But it seems to me the
>>> value
>>> of the droptol has never been changed. In that maillist thread, it was
>>> also
>>> mentioned that the dev-version is recommended, because of some bugs in
>>> the
>>> superlu interface. I have then compiled the current dev-version. but the
>>> problem is my program is based on another library (libMesh) which uses
>>> petsc
>>> as a solver package. Since some of the interfaces have been changed in
>>> the
>>> dev-version, I would not be able to compile the libMesh with petsc
>>> anymore.
>>> Is there anyway I can correct the superlu interface in the 3.1-p8 version
>>> directly? Any help will be appreciated!!
>>>
>>> Best regards
>>>
>>> --
>>> Ping Rong, M.Sc.
>>> Hamburg University of Technology
>>> Institut of modelling and computation
>>> Denickestraße 17 (Room 3031)
>>> 21073 Hamburg
>>>
>>> Tel.: ++49 - (0)40 42878 2749
>>> Fax:  ++49 - (0)40 42878 43533
>>> Email: ping.rong at tuhh.de
>>>
>>>
>
>
> --
> Ping Rong, M.Sc.
> Hamburg University of Technology
> Institut of modelling and computation
> Denickestraße 17 (Room 3031)
> 21073 Hamburg
>
> Tel.: ++49 - (0)40 42878 2749
> Fax:  ++49 - (0)40 42878 43533
> Email: ping.rong at tuhh.de
>
>