[petsc-users] extract arbitrary subset of a DMDA

[Matteo Semplice via petsc-users]

Dear all,

    I am wondering if there is a way to extract a subset of a DMDA and 
use it as a mesh. The use case is to program a finite-difference method 
in which the domain is defined by a levelset function: if I could 
completely ignore the parts of the background DMDA that are "far away" 
from the object, I guess I would avoid some cores having almost no 
workload. I figure that I could setup a DMDA, load/compute the levelset 
on the entire box, then mark the nodes to be retained, extract the 
submesh and repartition it. I would also need a mean to transfer some 
Vec data from the DMDA to the new mesh.

I guess that the extracted mesh would then become a DMPlex and it would 
not retain any DMDA flavour (like notions of which are the grid nodes 
sitting on top/bottom, left/right of a given node), right?

Thanks

    Matteo

--
Prof. Matteo Semplice
Università degli Studi dell’Insubria
Dipartimento di Scienza e Alta Tecnologia – DiSAT
Professore Associato
Via Valleggio, 11 – 22100 Como (CO) – Italia
tel.: +39 031 2386316