[petsc-dev] What's the point of D(A/M)GetGlobalVector?

[Matthew Knepley]

I would support a name change to Create().  However, we should be really
sure before we do stuff
like that since nothing pisses people off (Wolfgang) like name changes.

   Matt

On Fri, Aug 27, 2010 at 5:49 PM, Barry Smith <bsmith at mcs.anl.gov> wrote:

>
>  Hmmm,
>
> petscda.h:EXTERN PetscErrorCode PETSCDM_DLLEXPORT
>  DMGetColoring(DM,ISColoringType,const MatType,ISColoring*);
> petscda.h:EXTERN PetscErrorCode PETSCDM_DLLEXPORT  DMGetMatrix(DM, const
> MatType,Mat*);
> petscda.h:EXTERN PetscErrorCode PETSCDM_DLLEXPORT
>  DMGetInterpolation(DM,DM,Mat*,Vec*);
> petscda.h:EXTERN PetscErrorCode PETSCDM_DLLEXPORT
>  DMGetInterpolationScale(DM,DM,Mat,Vec*);
> petscda.h:EXTERN PetscErrorCode PETSCDM_DLLEXPORT
>  DMGetAggregates(DM,DM,Mat*);
>
>   should all of these be Create?
>
>   In my mind usually Get means get something intrinsic to the underlying
> object (some property of it for example);  Create means generate a new thing
> that while it may be associated with the DA is not "owned" or "controlled"
> by the DA.
>
>    Another way to organize is Create() implies you later Destroy() that
> object, while for things you Get you do something else (like restore).
>
>    I'm inclined to change all of these ones to Create() since they are all
> Destroyed()
>    Barry
>
>
>
> On Aug 27, 2010, at 11:10 AM, Jed Brown wrote:
>
> > On Fri, 27 Aug 2010 12:00:32 -0400, Kai Germaschewski <
> kai.germaschewski at unh.edu> wrote:
> >> And it also requires some more memory management framework which would
> >> call upon caches to expire long-unused objects when memory is running
> >> low.
> >
> > How would you detect this?  Note that further allocation may be done
> > external to PETSc, and perhaps even in a separate process.  We're not in
> > a managed environment, we can't get a reliable "time to GC".  If we
> > could get that sort of signal, then I would be for such caching at all
> > times, but I don't think we can, in which case I still think
> > managed/pooled access versus owned creation needs to be explicitly
> > different.
> >
> > Jed
>
>


-- 
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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