saving parallel vectors

[Barry Smith]

  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
> 
>