[petsc-users] DMDACreateSection

[Hui Zhang]

Hi petsc-group,

if I want to map a structured mesh onto processors by partition of mesh **elements**,
can I use DMDACreate3d -> DMDACreateSection, then DMDACreateLocal(Global)Vector to 
give me the vector corresponding to my Q1-element d.o.f.?

I ask because according to the manual, the usual use of DMDA is only for partition of 
**nodes** to processors and the local vector is not corresponding to partition of elements.
For example, consider the Q1 element on the 1D mesh, (numbers for nodes)

1--2--3--4--5

Given two processors, I want the local vector after partition to reside on the partitioned mesh

1--2--3   3--4--5  
proc 0    proc 1

The global value of d.o.f at the node 3 may be managed by proc 1, and proc 0 only ghosts it.
If it is the case, proc1 does not ghost any value.

This is different from the usual DMDA for finite difference stencils, in which the ghosting
is symmetric, i.e. both proc0 and proc1 will ghost some values.

Thanks in advance!