[petsc-users] Jacobian matrix for dual porosity model

[Matthew Knepley]

On Thu, Jun 22, 2017 at 12:59 AM, Adrian Croucher <a.croucher at auckland.ac.nz
> wrote:

> On 21/06/17 23:12, Matthew Knepley wrote:
>
>
> From the above description, its not clear to me that you want this
> topology. For example, in the case that each cell gets an internal cell,
> it seems like you could just handle this in the function space for each
> cell. Even for multiple internal cells, it seems like function space
> parameterization is a better option. Topology is supposed to indicate the
> support of basis functions, but here that job is done. I would
> just treat it as some sort of augmented approximation space.
>
>
> If I understand what you mean, I considered doing something like that-
> basically just defining extra degrees of freedom in the cells where dual
> porosity is to be applied.
>
> It seemed to me that if I then went ahead and created the Jacobian matrix
> using DMCreateMatrix(), it would give me extra nonzero entries that
> shouldn't be there - interactions between the dual porosity variables in
> neighbouring cells. Is there any way to avoid that?
>

Ah, this is a very good point. You would like sparse structure in the
Jacobian blocks. Currently I do not have it,
but DMNetwork does. I have been planning to unify the sparsity
determination between the two. It is on the list.

  Thanks,

    Matt


>
> - Adrian
>
> --
> Dr Adrian Croucher
> Senior Research Fellow
> Department of Engineering Science
> University of Auckland, New Zealand
> email: a.croucher at auckland.ac.nz
> tel: +64 (0)9 923 4611 <+64%209-923%204611>
>
>


-- 
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

http://www.caam.rice.edu/~mk51/
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