[petsc-users] How to use

[Sharp Stone]

Hi all,

I'm sorry I'm still confusing that if I have calculated the Jacobian
elements, how can I go ahead to solve the linear system with dof>1 at each
node? The example code ex19 solves the linear system with Guass-Seidel
method, and now I do want to use Jacobian matrix because I've found the
Jacobian elements. Any ideas? Many thanks!

On Thu, Oct 2, 2014 at 1:26 PM, Sharp Stone <thronesf at gmail.com> 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?
>
> Thank you in advance!
>
> On Thu, Oct 2, 2014 at 1:12 PM, Jed Brown <jed at jedbrown.org> wrote:
>
>> Sharp Stone <thronesf at gmail.com> 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
>



-- 
Best regards,

Feng
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