[petsc-users] Vec I/O using different parallel layout

[Mohamad M. Nasr-Azadani]

Thanks Barry,

I am still not 100% sure if I can do this.
Say I have save the global vector obtained by a DA (3D) that is shared
amongst 16 processors.
Can I load that data into a vector obtained from a DA (3D, same size
obviously) that is shared on 1 processor?

Thanks,
Best,
Mohamad


On Mon, Oct 10, 2011 at 5:36 PM, Barry Smith <bsmith at mcs.anl.gov> wrote:

>
> On Oct 10, 2011, at 7:31 PM, Mohamad M. Nasr-Azadani wrote:
>
> > Hi
> > I was wondering if it would be possible if I write a global vector
> (associated with a certain 3D distributed array)  to file
> > via:
> >
> >             ierr = PetscViewerBinaryOpen(PCW1, filename, FILE_MODE_WRITE,
> &writer);
> >             ierr = VecView(vec_data, writer);
> >             ierr = PetscViewerDestroy(writer);
> >
> > And then load the data into a global vector which is not created using
> the same parallel layout?
> > A simple example for this case would be to write the runtime data
> (parallel vector) to file and then just load the saved vector to do some
> simple SERIAL post processing.
>
>   YES.
>
>   The vector is saved to the file in the "natural ordering" that is
> starting with the logically 0,0,0 coordinate then increasing through the x
> axis, then the y axis then the z axis. To load back in in parallel you need
> to pass to VecLoad() a vector obtained with the appropriate
> DMCreateGlobalVector().
>
>
>  Barry
>
> >
> > Thanks in advance,
> > Best
> > Mohamad
> >
> >
> >
> >
>
>
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