[petsc-dev] Correct syntax for DMDA ownership ranges in petsc4py

[Matthew Knepley]

On Thu, Apr 7, 2016 at 2:14 PM, Chris Eldred <chris.eldred at gmail.com> wrote:

> I think what happens on the 1st version is that the input list has
> len(3), and since the DMDA only has 1 dimension petsc4py throws the
> first ValueError.
>

Yes, you are right.


> As far as I can tell, the code is expecting a list of lists: ie for
> each dimension it gets ranges[i] (where i is the index for the
> dimension) and casts it into an array. So I tried the 2nd version,
> which fails regardless of whether I use lists or tuples, and I don't
> understand why.


That function returns 'range' and the type is declared as tuple. Did you try

  ownership_ranges=((8,8,4),)

    Matt


>
> -Chris
>
> On Thu, Apr 7, 2016 at 9:00 PM, Matthew Knepley <knepley at gmail.com> wrote:
> > On Thu, Apr 7, 2016 at 1:52 PM, Chris Eldred <chris.eldred at gmail.com>
> wrote:
> >>
> >> Hey All,
> >>
> >> (I sent this to petsc-users a few days ago and didn't get any replies,
> >> figured I would try here as well...)
> >>
> >> Does anyone know the correct syntax for setting ownership ranges for
> >> DMDAs in petsc4py? For example, if I have a 1D DMDA with 20 vertices
> >> and 3 processes, and I want to distribute the vertices as [8,8,4],
> >> should the correct create call be:
> >>
> >> da =
> >>
> PETSc.DMDA().create(dim=1,dof=1,sizes=[20,],proc_sizes=[3,],boundary_type=[PETSc.DM.BoundaryType.PERIODIC,],
> >> stencil_type= PETSc.DMDA.StencilType.BOX,
> >> stencil_width=1,ownership_ranges=[8,8,4])
> >>
> >> or
> >>
> >> da =
> >>
> PETSc.DMDA().create(dim=1,dof=1,sizes=[20,],proc_sizes=[3,],boundary_type=[PETSc.DM.BoundaryType.PERIODIC,],
> >> stencil_type= PETSc.DMDA.StencilType.BOX,
> >> stencil_width=1,ownership_ranges=[[8,8,4],])
> >>
> >> For me, the 1st version fails with
> >> ValueError: number of dimensions 1 and number ownership ranges 3
> >> (which I expected)
> >> but the 2nd version also fails with
> >> TypeError: Expected tuple, got list
> >>
> >> I have tried using tuples instead of lists and nothing changes.
> >> Creating without the ownership_ranges argument works fine as well. Is
> >> there something else I am missing?
> >
> >
> > Here is the code:
> >
> >
> >
> https://bitbucket.org/petsc/petsc4py/src/b234a50085607b793fce93d5dc46307c0d9b57c4/src/PETSc/petscdmda.pxi?at=master&fileviewer=file-view-default#petscdmda.pxi-150
> >
> > I do not understand why the 1st version fails.
> >
> >    Matt
> >
> >>
> >> Thanks in advance for any assistance!
> >>
> >> Regards,
> >> -Chris
> >>
> >>
> >> --
> >> Chris Eldred
> >> Postdoctoral Fellow, LAGA, University of Paris 13
> >> PhD, Atmospheric Science, Colorado State University, 2015
> >> DOE Computational Science Graduate Fellow (Alumni)
> >> B.S. Applied Computational Physics, Carnegie Mellon University, 2009
> >> chris.eldred at gmail.com
> >
> >
> >
> >
> > --
> > 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
>
>
>
> --
> Chris Eldred
> Postdoctoral Fellow, LAGA, University of Paris 13
> PhD, Atmospheric Science, Colorado State University, 2015
> DOE Computational Science Graduate Fellow (Alumni)
> B.S. Applied Computational Physics, Carnegie Mellon University, 2009
> chris.eldred at gmail.com
>



-- 
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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