saving parallel vectors

[Satish Balay]

To complete your query - you'll also need a Vec with the same
communicator - i.e PETSC_COMM_SELF - for your approach to work.  One
way to do this is:

VecGetArray(vec,&v)
VecGetLocalSize(vec,size)
VecCreateSeqWithArray(MPI_COMM_SELF,size,v,&seqvec)

VecView(seqvec,seqviewer)

VecDestroy(seqvec)
VecRestoreArray(vec,&v)

Satish

On Thu, 23 Nov 2006, Barry Smith wrote:

> 
>   NEVER use ascii for large data sets. Use the binary viewer to save
> them. See PetscViewerBinaryOpen().
> 
>    Barry
> 
> 
> On Thu, 23 Nov 2006, Matteo Semplice wrote:
> 
> > This is really a newbie question but I am struggling to solve out of memory 
> > troubles on my first processor.
> > 
> > I have a parallel global vector, say v, that I obtain with a call to 
> > DAGetGlobalVector. I save it to disk opening an ASCII standard viewer on 
> > PETSC_COMM_WORLD and calling VecView. As I understand from the manual, this 
> > causes all processors to send their data to the first one and this one writes 
> > them to disk. This works fine for small computational grids, but hangs my 
> > program if the grid is bigger.
> > 
> > I am thinking to get each processor to write its own file and reassemble the 
> > data at the end of the program. I tried to create the viewer with the 
> > communicator PETSC_COMM_SELF and issue VecView. I get as many files as 
> > processors, but the first one contains all the data and the others are empty!
> > 
> > Why? And, more importantly, what's the best way to achieve my goal?
> > 
> > Thanks a lot.
> > 
> >      Matteo
> > 
> > 
> 
>