[Mpi-forum] MPI IO

[Jed Brown]

Amarpal Singh Kapoor <amarpalsinghkapoor at gmail.com> writes:

> Hello All,
>
> I intend to solve a Finite Element problem using MPI and PETSc. I have a
> conceptual problem with reading a mesh file in parallel with MPI IO.

The mpi-forum list is for discussions regarding the MPI standardization
process, not for general usage questions.  Please move this discussion
back to the PETSc mailing list or try discuss at mpich.org if the question
is specifically about MPI-IO.

> Unlike in the figure above I have a file which is different in structure
> (i.e. formatted with blocks of different size and datatypes) and I don't
> get how different blocks of data can be read in parallel. Should there be a
> synchronization call like MPI_BARRIER, after every block is completed on
> all processors? 

No, but you need to compute offsets for the parts to be read by each
process.