Re: [Libmesh-users] Initial guess for eigen problems

[Paul T. B. <ptb...@gm...>]

On Fri, Oct 21, 2016 at 5:24 AM, Hubert Weissmann <hu...@xe...> wrote:

> Hi,
>
> Thanks for pointing this out. With that, I can try to extend the
> interface, if I find time for this.
>
> Or are there plans to do it from the developers side?
>

AFAIK, there are no formal developer plans to do this. We'd love a Pull
Request!


>
> I think, it is really worth to implement since one could save much time
> from this.
>
> Best,
>
> Hubert
>
>
> On 21.10.2016 10:52, Julian Andrej wrote:
> > Hi,
> >
> > in the SLEPc EPS documentation [1] you can see that the initial
> > vectors have to be set explicitly, otherwise the initial vector is
> > initialized with random values.
> > You have to retrieve the EPS object somehow and set the initial
> > starting vector manually, as there is no method implemented for that,
> > yet. (No call to EPSSetInitialSpace in the libmesh sources)
> >
> > [1] http://slepc.upv.es/documentation/current/docs/manualpages/EPS/
> EPSSetInitialSpace.html#EPSSetInitialSpace
> >
> > On Fri, Oct 21, 2016 at 8:47 AM, Hubert Weissmann <hu...@xe...>
> wrote:
> >> Dear all,
> >>
> >> I wander whether one can set an initial guess to a (generalised)
> >> eigenproblem in LibMesh.
> >>
> >> In the mailing list I found this question posed twice, where Roy said he
> >> 'believes' that System::solution is used.
> >>
> >> However, I didn't any difference in performance whether I set
> >> System::solution somehow before solving or not (which may be due to a
> >> bad guess of course). However, I also didn't find any reference to it in
> >> the EigenSolver class (except in get_eigenpair() function where it is
> >> copied in the other direction).
> >>
> >> So my question is: Did I just seek in the wrong place or misunderstand
> >> the interface there or is it not possible to set an initial guess to
> >> slepc at this point?
> >>
> >> Any help is appreciated,
> >>
> >> Best,
> >>
> >> Hubert
> >>
> >>
> >>
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>
>
>
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