> 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.
Would that be with PetscSectionSetConstraintDof ? For that I will need the PetscSection, DofSection, within DMNetwork, how can I obtain it? I could cast it to DM_Network from the dm, networkdm, declared in the main program, maybe something like this: DM_Network *network = (DM_Network*) networkdm->data; Then I would loop over the vertices and call PetscSectionSetConstraintDof if it's a boundary node (by checking the corresponding component) Thanks for your responses. Miguel On Thu, Sep 25, 2014 at 2:42 PM, Jed Brown <j...@jedbrown.org> wrote: > Matthew Knepley <knep...@gmail.com> writes: > > > On Thu, Sep 25, 2014 at 1:46 PM, Abhyankar, Shrirang G. < > abhy...@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). > -- *Miguel Angel Salazar de Troya* Graduate Research Assistant Department of Mechanical Science and Engineering University of Illinois at Urbana-Champaign (217) 550-2360 salaz...@illinois.edu
