[petsc-users] Using GAMG to speed up solving of Poisson eqn

Sat Jul 20 09:08:23 CDT 2013

On Sat, Jul 20, 2013 at 8:39 AM, TAY wee-beng <zonexo at gmail.com> wrote:

>  Hi,
>
> I'm trying to use GAMG to speed up solving of Poisson eqn. I used:
>
> call KSPSetOptionsPrefix(ksp,"poisson_",ierr)
>
> -poisson_pc_gamg_agg_nsmooths 1 -poisson_pc_type gamg
>
> I remember it used to work in some problems but now it can't work, with
> error:
>

Upgrade to the latest release and we will help you debug this.

   Matt

> *[0]PETSC ERROR:
> ------------------------------------------------------------------------**
> **[0]PETSC ERROR: Caught signal number 8 FPE: Floating Point
> Exception,probably divide by zero**
> **[0]PETSC ERROR: Try option -start_in_debugger or
> -on_error_attach_debugger**
> **[0]PETSC ERROR: or see
> http://www.mcs.anl.gov/petsc/documentation/faq.html#valgrind[0]PETSC
> ERROR: or try http://valgrind.org on GNU/linux and Apple Mac OS X to find
> memory corruption errors**
> **[0]PETSC ERROR: likely location of problem given in stack below**
> **[0]PETSC ERROR: ---------------------  Stack Frames
> ------------------------------------**
> **[0]PETSC ERROR: Note: The EXACT line numbers in the stack are not
> available,**
> **[0]PETSC ERROR:       INSTEAD the line number of the start of the
> function**
> **[0]PETSC ERROR:       is given.**
> **[0]PETSC ERROR: [0] KSPComputeExtremeSingularValues_GMRES line 24
> src/ksp/ksp/impls/gmres/C:\wtay\DOWNLO~1\Codes\PETSC-~1\src\ksp\ksp\impls\gmres\gmreig.c
> **
> **[0]PETSC ERROR: [0] KSPComputeExtremeSingularValues line 40
> src/ksp/ksp/interface/C:\wtay\DOWNLO~1\Codes\PETSC-~1\src\ksp\ksp\INTERF~1\itfunc.c
> **
> **[0]PETSC ERROR: [0] PCGAMGOptprol_AGG line 1295
> src/ksp/pc/impls/gamg/C:\wtay\DOWNLO~1\Codes\PETSC-~1\src\ksp\pc\impls\gamg\agg.c
> **
> **[0]PETSC ERROR: [0] PCSetUp_GAMG line 564
> src/ksp/pc/impls/gamg/C:\wtay\DOWNLO~1\Codes\PETSC-~1\src\ksp\pc\impls\gamg\gamg.c
> **
> **[0]PETSC ERROR: [0] PCSetUp line 810
> src/ksp/pc/interface/C:\wtay\DOWNLO~1\Codes\PETSC-~1\src\ksp\pc\INTERF~1\precon.c
> **
> **[0]PETSC ERROR: [0] KSPSetUp line 182
> src/ksp/ksp/interface/C:\wtay\DOWNLO~1\Codes\PETSC-~1\src\ksp\ksp\INTERF~1\itfunc.c
> **
> **[0]PETSC ERROR: [0] KSPSolve line 351
> src/ksp/ksp/interface/C:\wtay\DOWNLO~1\Codes\PETSC-~1\src\ksp\ksp\INTERF~1\itfunc.c
> **
> **[0]PETSC ERROR: --------------------- Error Message
> ------------------------------------**
> **[0]PETSC ERROR: Signal received!**
> **[0]PETSC ERROR:
> ------------------------------------------------------------------------**
> **[0]PETSC ERROR: Petsc Development HG revision:
> 9850aeb5d33f0b33bc931843c4b3b3b4f8df6a3b  HG Date: Tue Oct 02 22:18:53 2012
> -0500**
> **[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:
> C:\Obj_tmp\ibm3d_high_Re_staggered_AB2\Debug\ibm3d_high_Re_staggered_AB2.exe
> on a petsc-3.3 named USER-PC by User Sat Jul 20 15:37:40 2013**
> **[0]PETSC ERROR: Libraries linked from
> /cygdrive/d/wtay/Lib/petsc-3.3-dev_win32_vs2008/lib**
> **[0]PETSC ERROR: Configure run at Thu Oct  4 10:01:13 2012**
> **[0]PETSC ERROR: Configure options --with-cc="win32fe cl"
> --with-fc="win32fe ifort" --with-cxx="win32fe cl"
> --with-mpi-dir=/cygdrive/c/MPICH2/ --download-f-blas-lapack=1
> --prefix=/cygdrive/d/wtay/Lib/petsc-3.3-dev_win32_vs2008 --with-debugging=1
> --useThreads=0**
> **[0]PETSC ERROR:
> ------------------------------------------------------------------------**
> **[0]PETSC ERROR: User provided function() line 0 in unknown directory
> unknown file**
> **application called MPI_Abort(MPI_COMM_WORLD, 59) - process 0**
> **
> **job aborted:**
> **rank: node: exit code[: error message]**
> **0: User-PC: 59: process 0 exited without calling finalize**
> *
>
> I read in one of the threads that I can use:
>
> -pc_type gamg -pc_gamg_agg_nsmooths 1 -mg_levels_ksp_type richardson
> -mg_levels_pc_type sor
>
> It worked but I got the msg:
>
> WARNING! There are options you set that were not used!
> WARNING! could be spelling mistake, etc!
> Option left: name:-mg_levels_ksp_type value: richardson
> Option left: name:-mg_levels_pc_type value: sor
> Option left: name:-pc_gamg_agg_nsmooths value: 1
> Option left: name:-pc_type value: gamg
> Press any key to continue . . .
>
> If I used this:
>
> -poisson_pc_type gamg -poisson_pc_gamg_agg_nsmooths 1
> -poisson_mg_levels_ksp_type richardson -poisson_mg_levels_pc_type sor
>
> It aborts with error:
>
> *[0]PETSC ERROR:
> ------------------------------------------------------------------------**
> **[0]PETSC ERROR: Caught signal number 8 FPE: Floating Point
> Exception,probably divide by zero**
> **[0]PETSC ERROR: Try option -start_in_debugger or
> -on_error_attach_debugger**
> **[0]PETSC ERROR: or see
> http://www.mcs.anl.gov/petsc/documentation/faq.html#valgrind[0]PETSC
> ERROR: or try http://valgrind.org on GNU/linux and Apple Mac OS X to find
> memory corruption errors**
> **[0]PETSC ERROR: likely location of problem given in stack below**
> **[0]PETSC ERROR: ---------------------  Stack Frames
> ------------------------------------**
> **[0]PETSC ERROR: Note: The EXACT line numbers in the stack are not
> available,**
> **[0]PETSC ERROR:       INSTEAD the line number of the start of the
> function**
> **[0]PETSC ERROR:       is given.**
> **[0]PETSC ERROR: [0] KSPComputeExtremeSingularValues_GMRES line 24
> src/ksp/ksp/impls/gmres/C:\wtay\DOWNLO~1\Codes\PETSC-~1\src\ksp\ksp\impls\gmres\gmreig.c
> **
> **[0]PETSC ERROR: [0] KSPComputeExtremeSingularValues line 40
> src/ksp/ksp/interface/C:\wtay\DOWNLO~1\Codes\PETSC-~1\src\ksp\ksp\INTERF~1\itfunc.c
> **
> **[0]PETSC ERROR: [0] PCGAMGOptprol_AGG line 1295
> src/ksp/pc/impls/gamg/C:\wtay\DOWNLO~1\Codes\PETSC-~1\src\ksp\pc\impls\gamg\agg.c
> **
> **[0]PETSC ERROR: [0] PCSetUp_GAMG line 564
> src/ksp/pc/impls/gamg/C:\wtay\DOWNLO~1\Codes\PETSC-~1\src\ksp\pc\impls\gamg\gamg.c
> **
> **[0]PETSC ERROR: [0] PCSetUp line 810
> src/ksp/pc/interface/C:\wtay\DOWNLO~1\Codes\PETSC-~1\src\ksp\pc\INTERF~1\precon.c
> **
> **[0]PETSC ERROR: [0] KSPSetUp line 182
> src/ksp/ksp/interface/C:\wtay\DOWNLO~1\Codes\PETSC-~1\src\ksp\ksp\INTERF~1\itfunc.c
> **
> **[0]PETSC ERROR: [0] KSPSolve line 351
> src/ksp/ksp/interface/C:\wtay\DOWNLO~1\Codes\PETSC-~1\src\ksp\ksp\INTERF~1\itfunc.c
> **
> **[0]PETSC ERROR: --------------------- Error Message
> ------------------------------------**
> **[0]PETSC ERROR: Signal received!**
> **[0]PETSC ERROR:
> ------------------------------------------------------------------------**
> **[0]PETSC ERROR: Petsc Development HG revision:
> 9850aeb5d33f0b33bc931843c4b3b3b4f8df6a3b  HG Date: Tue Oct 02 22:18:53 2012
> -0500**
> **[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:
> C:\Obj_tmp\ibm3d_high_Re_staggered_AB2\Debug\ibm3d_high_Re_staggered_AB2.exe
> on a petsc-3.3 named USER-PC by User Sat Jul 20 15:36:24 2013**
> **[0]PETSC ERROR: Libraries linked from
> /cygdrive/d/wtay/Lib/petsc-3.3-dev_win32_vs2008/lib**
> **[0]PETSC ERROR: Configure run at Thu Oct  4 10:01:13 2012**
> **[0]PETSC ERROR: Configure options --with-cc="win32fe cl"
> --with-fc="win32fe ifort" --with-cxx="win32fe cl"
> --with-mpi-dir=/cygdrive/c/MPICH2/ --download-f-blas-lapack=1
> --prefix=/cygdrive/d/wtay/Lib/petsc-3.3-dev_win32_vs2008 --with-debugging=1
> --useThreads=0**
> **[0]PETSC ERROR:
> ------------------------------------------------------------------------**
> **[0]PETSC ERROR: User provided function() line 0 in unknown directory
> unknown file**
> **application called MPI_Abort(MPI_COMM_WORLD, 59) - process 0**
> **
> **job aborted:**
> **rank: node: exit code[: error message]**
> **0: User-PC: 59: process 0 exited without calling finalize**
> *
>
>
> So is there a recommended test command or method?
>
> Thank!
>
> --
> Yours sincerely,
>
> TAY wee-beng
>
>

-- 
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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