[petsc-users] Get Stuck in SNES

[Matthew Knepley]

On Thu, Nov 24, 2011 at 5:00 AM, behzad baghapour <
behzad.baghapour at gmail.com> wrote:

>
>
> On Wed, Nov 23, 2011 at 4:33 PM, Jed Brown <jedbrown at mcs.anl.gov> wrote:
>
>> On Wed, Nov 23, 2011 at 01:06, behzad baghapour <
>> behzad.baghapour at gmail.com> wrote:
>>
>>>     for( c=0; c<ne; c++ ) for( p=0; p<tot; p++ )
>>>     FC->e[c].Q[p] = xx[c*(noe*num)+p];
>>>
>>
>> You haven't told me about "noe" or "num". Do you mean for this to read
>> xx[c*tot+p]?
>>
>
> noe is the number of equations (equal to number of flow states) and num is
> the number of shape functions in element (according to the order of
> accuracy)
>
>>
>>
>>>
>>>     ierr = VecRestoreArray( x, &xx ); CHKERRQ( ierr );
>>>
>>>     interiorFlux( FC->flw, FC->e );
>>>     faceFlux    ( FC->flw, FC->f, FC->e );
>>>
>>
>> The first of these should set FC->e (if you are adding into it, then you
>> need to zero it first) and the second should add into it.
>>
>
> I found that my mistake is that I forgot to set upwind effect in my
> defined field context. The problem was not stable, it is not related to
> SNES setup.
>
> However, I can't find out the difference between "basic" and
> "basicnonorms" in line search method.
>

Basic takes the full Newton step, but checks for decrease. nonorms just
takes it and moves on.


> In addition, Is it possible to set the number of line-search corrections
> or is just decided by the solver?
>

You can set a custom line search. I am not sure what you mean by this
"number of line search correctons"

   Matt


> Thanks a lot,
> BehZad
>
>
>


-- 
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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