[petsc-users] Geometric multigrid with a cell-centered discretization

Tue Jan 9 16:15:28 CST 2018

> you need to not attach any
> coordinates to your DMDA and it should work. See for example
> src/ksp/ksp/examples/tutorials/ex32.c

You mean, I should omit the call to DMDASetUniformCoordinates, right? This means, that my Paraview files will have no domain size info anymore. 

I will try it tomorrow and come back to you with the results. 

Thank you!
Henrik

> 
>   Barry
> 
> Sorry about this, someone needs to fix the injection for Q0 case.
> 
> 
> > On Jan 9, 2018, at 9:12 AM, Buesing, Henrik <hbuesing at eonerc.rwth-
> aachen.de> wrote:
> >
> > Sorry (again), for posting only part of the error message...
> >
> > So, here it comes. I will first [1] show the code snippets I am using, then
> second [2] I will show the PETSc options, and finally [3] the error message I
> get.
> > The grid is 1536 x 1 x 256 in x,y,z-direction. Thus, we see the first level of
> coarsening in x-direction here.
> >
> > Thank you!
> > Henrik
> >
> > [1]
> >        CALL
> DMDACreate3d(PETSC_COMM_WORLD,DM_BOUNDARY_GHOSTED,DM_BO
> UNDARY_GHOSTED,DM_BOUNDARY_GHOSTED,&
> >                        DMDA_STENCIL_STAR, I0g,J0g,K0g, PETSC_DECIDE,
> PETSC_DECIDE,PETSC_DECIDE, petsc_two, petsc_one, &
> >
> PETSC_NULL_INTEGER,PETSC_NULL_INTEGER,PETSC_NULL_INTEGER,
> petsc_da, petsc_ierr)
> >        CALL DMSetUp(petsc_da,petsc_ierr) ...
> >        CALL DMSetFromOptions(petsc_da, petsc_ierr)
> >        CALL DMDASetInterpolationType(petsc_da, DMDA_Q0, petsc_ierr)
> >        CALL SNESSetDM(petsc_snes, petsc_da, petsc_ierr)
> >        CALL SNESSetFromOptions(petsc_snes,petsc_ierr)
> >
> > [2] -snes_monitor -snes_linesearch_monitor -snes_type newtonls
> > -snes_linesearch_type basic -ksp_type fgmres -ksp_max_it 1000
> > -snes_stol 1e-06 -snes_rtol 1e-06 -snes_atol 1e-6 -ksp_gmres_restart
> > 100 -ksp_monitor -pc_type mg -da_refine_y 1 -ksp_converged_reason
> > -snes_converged_reason -ksp_monitor -ksp_view -pc_mg_levels 2
> > -options_left
> >
> > [3]
> > [0]PETSC ERROR: --------------------- Error Message
> > --------------------------------------------------------------
> > [0]PETSC ERROR: Arguments are incompatible [0]PETSC ERROR: Ratio
> > between levels: (mx - 1)/(Mx - 1) must be integer: mx 1536 Mx 768
> > [0]PETSC ERROR: See
> http://www.mcs.anl.gov/petsc/documentation/faq.html for trouble
> shooting.
> > [0]PETSC ERROR: Petsc Development GIT revision: v3.8.2-48-g851ec02
> > GIT Date: 2017-12-05 09:52:17 -0600 [0]PETSC ERROR:
> >
> /rwthfs/rz/cluster/work/hb111949/EoCoE/aixcelerate17/gge_gnu/bench_ru
> n
> > /000023/000000_copy_sub_launch/work/shem_fw64gnu_const.x on a
> > gnu_openmpi named linuxbmc0008.rz.RWTH-Aachen.DE by hb111949 Tue
> Jan
> > 9 16:04:39 2018 [0]PETSC ERROR: Configure options
> > --download-fblaslapack --with-cc=mpicc -with-fc=mpif90
> > --with-cxx=mpicxx --download-hypre --download-superlu_dist
> > --download-suitesparse --download-scalapack --download-blacs
> > --download-hdf5 --download-parmetis --download-metis
> > --with-debugging=0 --download-mumps [0]PETSC ERROR: #1
> > DMCreateInjection_DA_3D() line 1195 in
> >
> /rwthfs/rz/cluster/work/hb111949/Code/petsc/src/dm/impls/da/dainterp.c
> > [0]PETSC ERROR: #2 DMCreateInjection_DA() line 1283 in
> >
> /rwthfs/rz/cluster/work/hb111949/Code/petsc/src/dm/impls/da/dainterp.c
> > [0]PETSC ERROR: #3 DMCreateInjection() line 1082 in
> > /rwthfs/rz/cluster/work/hb111949/Code/petsc/src/dm/interface/dm.c
> > [0]PETSC ERROR: #4 DMCoarsen_DA() line 1219 in
> > /rwthfs/rz/cluster/work/hb111949/Code/petsc/src/dm/impls/da/da.c
> > [0]PETSC ERROR: #5 DMCoarsen() line 2427 in
> > /rwthfs/rz/cluster/work/hb111949/Code/petsc/src/dm/interface/dm.c
> > [0]PETSC ERROR: #6 PCSetUp_MG() line 618 in
> > /rwthfs/rz/cluster/work/hb111949/Code/petsc/src/ksp/pc/impls/mg/mg.c
> > [0]PETSC ERROR: #7 PCSetUp() line 924 in
> > /rwthfs/rz/cluster/work/hb111949/Code/petsc/src/ksp/pc/interface/preco
> > n.c [0]PETSC ERROR: #8 KSPSetUp() line 381 in
> > /rwthfs/rz/cluster/work/hb111949/Code/petsc/src/ksp/ksp/interface/itfu
> > nc.c [0]PETSC ERROR: #9 KSPSolve() line 612 in
> > /rwthfs/rz/cluster/work/hb111949/Code/petsc/src/ksp/ksp/interface/itfu
> > nc.c [0]PETSC ERROR: [1]PETSC ERROR: --------------------- Error
> > Message --------------------------------------------------------------
> >
> >
> > --
> > Dipl.-Math. Henrik Büsing
> > Institute for Applied Geophysics and Geothermal Energy E.ON Energy
> > Research Center RWTH Aachen University
> > ------------------------------------------------------
> > Mathieustr. 10            |    Tel +49 (0)241 80 49907
> > 52074 Aachen, Germany     |    Fax +49 (0)241 80 49889
> > ------------------------------------------------------
> > http://www.eonerc.rwth-aachen.de/GGE
> > hbuesing at eonerc.rwth-aachen.de
> > ------------------------------------------------------
> >
> >> -----Ursprüngliche Nachricht-----
> >> Von: Smith, Barry F. [mailto:bsmith at mcs.anl.gov]
> >> Gesendet: 09 January 2018 15:10
> >> An: Buesing, Henrik <hbuesing at eonerc.rwth-aachen.de>
> >> Cc: petsc-users <petsc-users at mcs.anl.gov>
> >> Betreff: Re: [petsc-users] Geometric multigrid with a cell-centered
> >> discretization
> >>
> >>
> >>  With cell centered elements each element is sliced in half in each
> >> of the three directions for refinement (or you can refine only in 1
> >> or 2 of the dimensions if you like). This means that the ratio of mx
> >> to MX needs to be 2 (or 4).So your numbers are fine.
> >>
> >>> On Jan 9, 2018, at 7:59 AM, Buesing, Henrik <hbuesing at eonerc.rwth-
> >> aachen.de> wrote:
> >>>
> >>> Dear all,
> >>>
> >>> I am using DMDACreate3d to generate my domain and a cell-centered
> >>> two-point flux approximation as discretization. I use geometric
> >>> Multigrid (-pc_type mg) with DMDASetInterpolationType(petsc_da,
> >>> DMDA_Q0, petsc_ierr). With DM_BOUNDARY_GHOSTED as boundary
> type in
> >>> DMDACreate3d, I get
> >>>
> >>> [0]PETSC ERROR: Arguments are incompatible [0]PETSC ERROR: Ratio
> >>> between levels: (mx - 1)/(Mx - 1) must be integer: mx 1536 Mx 768
> >>
> >>  We need ALL the output from the error (always). It should never be
> >> doing this check in your case so something is wrong with the order of
> >> your code perhaps.
> >>
> >>   Barry
> >>
> >>>
> >>> With DM_BOUNDARY_PERIODIC, I get invalid accesses when I assemble
> >>> the
> >> matrix.
> >>>
> >>> Can I somehow tell him, that I have a cell-centered grid, or do I
> >>> have
> >> to resort to using N+1 in my dimensions?
> >>>
> >>> Thank you!
> >>> Henrik
> >>>
> >>>
> >>> --
> >>> Dipl.-Math. Henrik Büsing
> >>> Institute for Applied Geophysics and Geothermal Energy E.ON Energy
> >>> Research Center RWTH Aachen University
> >>> ------------------------------------------------------
> >>> Mathieustr. 10            |    Tel +49 (0)241 80 49907
> >>> 52074 Aachen, Germany     |    Fax +49 (0)241 80 49889
> >>> ------------------------------------------------------
> >>> http://www.eonerc.rwth-aachen.de/GGE
> >>> hbuesing at eonerc.rwth-aachen.de
> >>> ------------------------------------------------------
> >