[petsc-dev] SNES, Coloring, DM, and TS

[Jed Brown]

On Mon, Feb 27, 2012 at 11:21, Matthew Knepley <knepley at gmail.com> wrote:

> Having DM hold the callbacks is a problem. But don't we have them in the
> context arg?
>

PetscErrorCode SNESDMComputeJacobian(SNES snes,Vec X,Mat *J,Mat
*B,MatStructure *flag,void *ptr)
{
  PetscErrorCode ierr;
  DM             dm;

  PetscFunctionBegin;
  ierr = SNESGetDM(snes,&dm);CHKERRQ(ierr);
  ierr = DMComputeJacobian(dm,X,*J,*B,flag);CHKERRQ(ierr);
  PetscFunctionReturn(0);
}

The SNES is not available from the callback.


> Aren't they just passed in? Or do you mean auxiliary vectors?


Auxiliary vectors. In this case, they are used by TS to convert the
semi-discrete form provided by the user into the fully discrete form being
solved by SNES.
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