Getting values of a parallel vector

[Satish Balay]

On Mon, 24 Mar 2008, Jaime Suarez wrote:

> Good morning,
> 
> My question is about getting the values of a parallel vector in the
> PETSc subroutines using Fortran 90.
> 
> As far as I know, I can invoke:
> CALL VecGetArrayF90
> in order to get the full array that is being considered in each
> processor. However, I cannot employ this tool since I need to have also
> the values that are stored in other processors. Is there a straight way
> to get the value of the n-th element of a parallel vector, no matter
> where this element is stored?
> 
> I am aware of the difficulty of this task, since it would involve
> transfer of information between different processors.
> 
> Thanking you in advance,

Check the manpage for VecScatterCreate(). You'll have to create
the VecScatter object corresponding to the off-proc values you
need - and then scatter them.

After the scatter, the values will be available locally [Now you can
use VecGetArrayF90 to access the values]

Satish