[petsc-users] DMPlex with spring elements

[Jed Brown]

Matthew Knepley <knepley at gmail.com> writes:

> On Thu, Sep 25, 2014 at 1:46 PM, Abhyankar, Shrirang G. <abhyshr at mcs.anl.gov
>> wrote:
>
>> You are right. The Jacobian for the power grid application is indeed
>> non-symmetric. Is that a problem for your application?
>>
>
> If you need a symmetric Jacobian, you can use the BC facility in
> PetscSection, which eliminates the
> variables completely. This is how the FEM examples, like ex12, work.

You can also use MatZeroRowsColumns() or do the equivalent
transformation during assembly (my preference).
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