Hi,
thanks for the answers first of all. I have another question though ... :)
Say, i want to print a specific element from a PETSc global vector. Is there a
function (PetscSunchFPrintF does not do this i believe) to which i simply
pass the file handle, communicator, the vector and the element and it writes
the value to the file?
No, this function does not currently exist. Are these elements local? If not, it
would entail communication. If so, you could use VecGetArray() and then just
index in. Is that sufficient?
thanks,
Matt
thanks
mat
On Wednesday 13 September 2006 17:13, Berend van Wachem wrote:
> Hi Matt,
>
> > i need to read in an input file. So to open my file i use PETSCFOpen
> > which works fine. But then my problems begin ... :)
> >
> > I guess i need to tell only the first proc in the communicator to fscan.
> > But is there a PETSC function that returns me the processor id?
> > And when i read the parameters in on the first proc i need to broadcast
> > them to the other procs. Does PETSC have anything for this?
>
> For both issues you can use standard MPI:
>
> to get the processor ID:
> ierr=MPI_Comm_rank(MPI_Comm Communicator,int *rank);
>
> to broadcast information:
> ierr=MPI_Bcast ( void *buffer, int count, MPI_Datatype datatype, int
> root, MPI_Comm comm )
>
> If possible, I would recommend you to use the PetscViewer interface for
> your IO handling; it is very easy.
>
> Good luck,
>
> Berend.