[petsc-users] Global Numbering

[Matthew Knepley]

On Wed, Mar 21, 2018 at 1:28 PM, Mohammad Hassan Baghaei <
mhbaghaei at mail.sjtu.edu.cn> wrote:

> I am trying to fill a vector based on global coordinate.
>

You can see how this might be too vague for me to follow.


> As I am trying to use VecGetValues() on the global coordinate,
>

Okay, this does not work for any parallel vector.


> I find it that argument goes out of range, since I am using global
> numbering rather than local numbering.
>

It is not the numbering that is a problem. It is that parallel Vectors in
PETSc are distributed. You cannot directly access
data you do not own. You can send it to one process (for example using
VecScatterCreateToZero()), but this is of course
not scalable.

  Thanks,

    Matt


> *From:* Matthew Knepley [mailto:knepley at gmail.com]
> *Sent:* Wednesday, March 21, 2018 10:38 PM
> *To:* Mohammad Hassan Baghaei <mhbaghaei at mail.sjtu.edu.cn>
> *Cc:* PETSc <petsc-users at mcs.anl.gov>
> *Subject:* Re: [petsc-users] Global Numbering
>
>
>
> On Wed, Mar 21, 2018 at 8:18 AM, Mohammad Hassan Baghaei <
> mhbaghaei at mail.sjtu.edu.cn> wrote:
>
> Hello
>
> I am trying to create a global vector of coordinates based on the
> parallelized dm. I find it really hard to work with the local numbering,
> how can I manage to create a kind of numbering on global level so that I
> could easily access to the nodes based on the new numbering. Thanks for
> your time.
>
>
>
> DMGetCoordinates() gives you a global vector.
>
> DMGetCoordinatesLocal() gives you a local vector.
>
>
>
> What are you trying to do?
>
>
>
>   Thanks,
>
>
>
>      Matt
>
>
>
> Amir
>
>
>
>
>
> --
>
> 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
>
>
>
> https://www.cse.buffalo.edu/~knepley/ <http://www.caam.rice.edu/~mk51/>
>



-- 
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

https://www.cse.buffalo.edu/~knepley/ <http://www.caam.rice.edu/~mk51/>
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.mcs.anl.gov/pipermail/petsc-users/attachments/20180321/e685d68d/attachment.html>