[petsc-users] Solving Poisson equation with multigrid

[Jed Brown]

Michele Rosso <mrosso at uci.edu> writes:

> I added KSPSetDM() and now the error I receive is:
>
> [0]PETSC ERROR: --------------------- Error Message 
> ------------------------------------
> [0]PETSC ERROR: No support for this operation for this object type!
> [0]PETSC ERROR: For coloring efficiency ensure number of grid points in 
> X is divisible
>                   by 2*stencil_width + 1
> !
> [0]PETSC ERROR: 
> ------------------------------------------------------------------------
> [0]PETSC ERROR: Petsc Release Version 3.3.0, Patch 3, Wed Aug 29 
> 11:26:24 CDT 2012
> [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: ./hit on a  named nid25119 by Unknown Fri May 17 
> 17:41:05 2013
> [0]PETSC ERROR: Libraries linked from
> [0]PETSC ERROR: Configure run at
> [0]PETSC ERROR: Configure options
> [0]PETSC ERROR: 
> ------------------------------------------------------------------------
> [0]PETSC ERROR: DMCreateColoring_DA_3d_MPIAIJ() line 288 in 
> src/dm/impls/da/fdda.c
> [0]PETSC ERROR: DMCreateColoring_DA() line 172 in src/dm/impls/da/fdda.c
> [0]PETSC ERROR: DMCreateColoring() line 709 in src/dm/interface/dm.c
> [0]PETSC ERROR: DMComputeJacobian() line 2206 in src/dm/interface/dm.c
> [0]PETSC ERROR: KSPSetUp() line 228 in src/ksp/ksp/interface/itfunc.c
>
>
> My 3D grid is composed by 256^3 nodes, I am using 4 processors and the 
> the DMDA is initialized as:

Yes, with a vertex-centered discretization, use 257^3 instead.