[petsc-users] DOF projection after dmforest adaption

[Matthew Knepley]

On Fri, Mar 14, 2025 at 12:15 PM Preda Silvia via petsc-users <
petsc-users at mcs.anl.gov> wrote:

> Hi,
>
>
>
> We are having a hard time understanding how the degrees of freedom are
> projected after a dmforest adaption. Having used before the P4EST library
> directly, we recall that there, a index mapping from quadrants present in
> the grid before and after adaption (1 to 1, 1 to many, many to 1, for
> unaltered, refined, coarsened quadrants, respectively) was available. Would
> it be possible to access the same information for a dmforest?
>
>
>
> Thank you for all the suggestion!
>

I do not understand exactly what you want yet.

A projection of the dofs would necessarily depend on the function space you
are using to represent the field.

So you might instead be asking, can I get the  refinement pattern like the
parent of a given cell. You can get this

  https://urldefense.us/v3/__https://petsc.org/main/manualpages/DMPlex/DMPlexGetTreeParent/__;!!G_uCfscf7eWS!aAk0LSbDAPHyCjCzQ3Fa3FjQxqV-5Cx8PkJvYW2BWAfdWeBJcXe9U9MriWyHncDo0mnS_NKfIJJCq7vFlz-x$ 

There are few users (except us), so we would be happy to listen to
interface suggestions. I will also note that Toby is
the expert, and I am an amateur.

  Thanks,

     Matt


> Silvia
>


-- 
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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