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

Smith, Barry F. bsmith at mcs.anl.gov
Tue Jan 9 16:38:58 CST 2018 


> On Jan 9, 2018, at 4:15 PM, Buesing, Henrik <hbuesing at eonerc.rwth-aachen.de> wrote:
> 
>> 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?

 I guess.

> This means, that my Paraview files will have no domain size info anymore. 

  Presumably. But you may be able to work around the issue some way, for example setting the coordinates after the solvers are complete. 

 Barry

> 
> 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
>>>>> ------------------------------------------------------
>>> 
>

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