[petsc-users] Weighted Jacobi

[Timothée Nicolas]

I meant

X^{k+1} = omega*D^{-1}*(b - (A-D)*X^k) + (1-omega)*X^k

This is what the wikipedia page says about weighted Jacobi :
https://en.wikipedia.org/wiki/Jacobi_method#Weighted_Jacobi_method. It is
easy to hard code anyway.

Thx

Timothée


2015-12-01 23:10 GMT+09:00 Matthew Knepley <knepley at gmail.com>:

> Or do you mean
>
>   *-pc_jacobi_type rowsum*
>
> *  Thanks,*
>
> *    Matt*
>
> On Tue, Dec 1, 2015 at 3:26 AM, Timothée Nicolas <
> timothee.nicolas at gmail.com> wrote:
>
>> OK, I'll look at that, thanks
>>
>> Timothee
>>
>> 2015-12-01 18:02 GMT+09:00 Dave May <dave.mayhem23 at gmail.com>:
>>
>>> I believe what you are looking for is defined by the following options
>>>   -ksp_type richardson
>>>   -ksp_richardson_scale <value>
>>>   -pc_type jacobi
>>>
>>> Thanks,
>>>   Dave
>>>
>>> On 1 December 2015 at 08:57, Timothée Nicolas <
>>> timothee.nicolas at gmail.com> wrote:
>>>
>>>> Hi all,
>>>>
>>>> Is weighted Jacobi available as a preconditioner ? I can't find it in
>>>> the list of preconditioners. If not, what is the rationale between this
>>>> choice ? It is pretty straightforward to code, so if it is not available I
>>>> can do it without problem I guess, but I am just wondering. In the
>>>> matrix-free case where SOR is not available by default, it may be better
>>>> than pure Jacobi, and much easier to parallelize than SOR.
>>>>
>>>> Best
>>>>
>>>> Timothee
>>>>
>>>
>>>
>>
>
>
> --
> 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
>
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