On 10/2/14 7:26 PM, Sharp Stone wrote:
Hi Matt and Jed,
Thank you very much for your replies. In source code ex19, the routine
SNESSetNGS() is used, and no other options or Jacobi routines are
used. How can we change the iteration method? The routine
SNESSetFromOptions(snes) could do this for the user? If I understand
correctly, petsc would use Gauss-Seidel or Jacobi method as designated
with even the same source code?
Yes, and this applies for other objects as well. The important thing, in
general, is to call XXXSetFromOptions after you have set any default
options with XXXSetYYY, but before you call XXXSetUp (which does things
like allocate memory). This allows you to set whichever defaults make
sense, and also control things from the command line.
Thank you in advance!
On Thu, Oct 2, 2014 at 1:12 PM, Jed Brown <[email protected]
<mailto:[email protected]>> wrote:
Sharp Stone <[email protected] <mailto:[email protected]>> writes:
> Matt,
>
> Thank you very much!
>
> The ex19 used the Gauss-Seidel method. But I'm a little bit
wonder whether
> we have any examples of Jacobi method to solve such linear
systems "(mat)A
> dot (vec)X = (vec)B" with dof>1? Thanks in advance!
ex19 does whatever you want: -pc_type jacobi and the like.
--
Best regards,
Feng
