[petsc-users] Arbitrary ownership IS for a matrix

[Matthew Knepley]

On Wed, Mar 9, 2022 at 5:13 PM Barry Smith <bsmith at petsc.dev> wrote:

>
>   You need to do a mapping of your global numbering to the standard PETSc
> numbering and use the PETSc numbering for all access to vectors and
> matrices.
>
>    https://petsc.org/release/docs/manualpages/AO/AOCreate.html provides
> one approach to managing the renumbering.
>

You can think of this as the mapping to offsets that you would need in any
event to store your values (they could not be directly addressed with your
random indices).

  Thanks,

     Matt


>   Barry
>
>
> On Mar 9, 2022, at 3:42 PM, Nicolás Barnafi <nabw91 at gmail.com> wrote:
>
> Hi community,
>
> I have an application with polytopal meshes (elements of arbitrary shape)
> where the distribution of dofs is not PETSc friendly, meaning that it is
> not true that cpu0 owns dofs [0,a), then cpu1 owns [a,b) and so on, but
> instead the distribution is in fact random. Another important detail is
> that boundary dofs are shared, meaning that if dof 150 is on the boundary,
> each subdomain vector has dof 150.
>
> Under this considerations:
>
> i) Is it possible to give an arbitrary mapping to the matrix structure or
> is the blocked distribution hard coded?
> ii) Are the repeated boundary dofs an issue when computing a Fieldsplit
> preconditioner in parallel?
>
> Best regards,
> Nicolas
>
>
>

-- 
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.cse.buffalo.edu/~knepley/>
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.mcs.anl.gov/pipermail/petsc-users/attachments/20220309/d961ca48/attachment.html>