[petsc-users] DMPlex ghost cells

[Adrian Croucher]

I am adding cells onto a DMPlex (for dual porosity). I notice that 
normally the ghost cells in a DMPlex are at the end of the cell list.

Does it matter if the cells I add come after those ghost cells, or 
should the ghosts always come last?

It seems to me it probably shoudn't matter if the partition ghosts 
(created by DMPlexDistribute()) are not at the end. In my cell loops I 
just check the value of the ghost DMLabel and skip them if necessary.

But perhaps the boundary ghosts (created by DMPlexConstructGhostCells()) 
need to come last? Otherwise the output from DMPlexGetHybridBounds() (to 
get the bounds on 'interior' cells, i.e. non-boundary-ghosts) probably 
wouldn't make much sense?

- Adrian

-- 
Dr Adrian Croucher
Senior Research Fellow
Department of Engineering Science
University of Auckland, New Zealand
email: a.croucher at auckland.ac.nz
tel: +64 (0)9 923 4611