[petsc-users] How to display the actual Jacobian generated by SNES with fdcoloring?

[Jed Brown]

On Sun, Oct 14, 2012 at 7:14 AM, Bao Kai <paeanball at gmail.com> wrote:

> Hi, all,
>
> I want to check the exact Jacobian generated by SNES with fdcoloring with
> some small size problems.  I mean to display the actual matrix and rhs.
>

You can use -snes_type test -snes_test_display or -snes_compare_explicit to
"compare" the assembled matrix to one computed using FD. If you combine
-snes_fd -snes_compare_explicit, the two matrices will be the same, but
both will be printed.

You can also call SNESDefaultComputeJacobian() and MatView() directly from
your code.


>
> Could you please help to tell me how I can do that?
>
> Thank you.
>
> Best Regards,
> Kai
>
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