[petsc-users] global index distributed arrays

Matthew Knepley knepley at gmail.com
Fri Dec 10 18:40:43 CST 2010


On Fri, Dec 10, 2010 at 11:46 PM, Mohamad M. Nasr-Azadani
<mmnasr at gmail.com>wrote:

> Hi guys,
>
> I was wondering if there is an easy way of accessing the global index of a
> node which is not within the local and ghost node regions on every processor
> for DA.
> To be more more specific, I am trying to setup a matrix based on a
> three-dimensional DA. (Star stencil, width=1).
> For some special nodes, I need to insert nonzero values which do not fit in
> the local plus the ghost regions of the DA.
> I know that I can not use MatSetValuesStencil anymore, but I still can use
> MatSetValues. But I need to know the global index of those nodes.
> I tried to use DAGetGlobalIndices(), but that would again return the global
> indices of the local plus ghost nodes on current processor.
> I know that I could use some MPI commands to pass those indices among
> processors, but I was wondering if there a clean and neat way with which
> each processor can have access to the global index for any given 3-d index.
>

((k*N + j)*M + i)*C + c

   Matt


> Thank,
> Mohamad
>
>
>


-- 
What most experimenters take for granted before they begin their experiments
is infinitely more interesting than any results to which their experiments
lead.
-- Norbert Wiener
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