Matthew Knepley knepley at
Wed Jan 14 12:03:24 CST 2009

On Wed, Jan 14, 2009 at 11:25 AM, Tim Kroeger <
tim.kroeger at> wrote:

> Dear PETSc team,
> When I create a vector using VecCreateGhost(), and later on I want to
> access the value of one of the ghost cells, and all I know is the *global*
> index of that value, what is the correct thing to do?  I understand that the
> ghost values are stored at the end of the vector and that this is done in
> the order that I used when creating the vector, but do I have to remember
> that order myself, or is there some method to query the local index
> corresponding to a global index?

Unfortunately, we never create the inverse mapping.


> Best Regards,
> Tim
> --
> Dr. Tim Kroeger
> tim.kroeger at            Phone +49-421-218-7710
> tim.kroeger at            Fax   +49-421-218-4236
> Fraunhofer MEVIS, Institute for Medical Image Computing
> Universitaetsallee 29, 28359 Bremen, Germany

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