[petsc-dev] ASPIN and SNESSetType

[Stefano Zampini]

I'll open a pull request
Il 01/ott/2015 10:28 PM, "Barry Smith" <bsmith at mcs.anl.gov> ha scritto:

>
>   Matt is at least partially right, having this as a SNESType is
> questionable. It is actually a specific nonlinear preconditioner PLUS a
> specific set of options for the NewtonLS SNES method. I also understand why
> Peter did it this way because there is no clean "other way" to provide this
> functionality that is not ad hoc.
>
>   I think the correct short term fix is to add a SNESDestroy_ASPIN() that
> does delete the npc and then calls the SNESDestroy_NewtonLS()
>
>   Stefano,
>
>     Are you willing to make a pull request or patch to do this?
>
>    Thanks for letting us know about this problem
>
>   Barry
>
>
> > On Oct 1, 2015, at 12:43 PM, Matthew Knepley <knepley at gmail.com> wrote:
> >
> > On Thu, Oct 1, 2015 at 7:42 AM, Stefano Zampini <
> stefano.zampini at gmail.com> wrote:
> > I just noticed that the behaviour of a code like this
> >
> > SNESSetType(snes,SNESASPIN)
> > SNESSetFromOptions(snes)
> >
> > is not the same as
> >
> > SNESSetType(snes,SNESNEWTONLS)
> > SNESSetFromOptions(snes)
> >
> > when -snes_type newtonls is specified at command line. In both cases,
> the snes will be of type SNESNEWTONLS, but in the first case, the snes
> object will also have a nonlinear preconditioner embedded in, since
> SNESASPIN creates snes->pc, and there's no SNESDestroy_ASPIN.
> >
> > What is the correct approach to fix this? Should the nonlinear
> preconditioner be destroyed by the SNESSetType interface or by the specific
> implementation of ASPIN?
> >
> > I wish Peter had not done it this way. His reason was that a special
> Jacobian action can be defined for
> > Newton -L NASM, but we should just do this with a flag rather than a new
> SNES type.
> >
> >    Matt
> >
> >
> > --
> > Stefano
> >
> >
> >
> > --
> > 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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