[petsc-users] Get stiffness matrix by using Petsc's functions

[Matthew Knepley]

On Tue, Jul 23, 2019 at 2:45 AM Tsung-Hsing Chen via petsc-users <
petsc-users at mcs.anl.gov> wrote:

> Hi,
> I'am using Petsc to solve FEM problems.
> Right now I just use MatSetValue() or MatSetValues() to build up the
> stiffness matrix.
> I wonder can I easily get stiffness matrix by using Petsc's functions.
> By the way, I'am using unstructured grid (DMPlex).
>

PETSc has some support to generate very simple FEM problems. Almost
everything we can do is shown
in examples. For instance,

  SNES ex12: Poisson
  SNES ex17: Elasticity
  SNES ex62: Stokes
  SNES ex69: nonlinear Stokes
  SNES ex77: large deformation Elasticity
  TS      ex45: Heat equation
  TS      ex46: Navier-Stokes

If those look understandable, then maybe this system is capable of
generating your problem.

  Thanks,

     Matt

Thanks a lot for your help,
> Tsung-Hsing Chen
>


-- 
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/>
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