.. default-domain:: chpl

.. module:: IOusingMPI
   :synopsis: HDF5 routines that rely on MPI.

IOusingMPI
==========
**Usage**

.. code-block:: chapel

   use HDF5.IOusingMPI;


or

.. code-block:: chapel

   import HDF5.IOusingMPI;

HDF5 routines that rely on MPI.

A module to encapsulate functions that use the MPI module so that it
is not initialized unless these functions are actually used.


.. function:: proc hdf5WriteDistributedArray(A: [], filename: string, dsetName: string)

   Write the Block distributed Array `A` as an HDF5 dataset named `dsetName`
   in the file `filename` using parallel collective IO. This requires the
   hdf5-parallel library, which requires the MPI library.
   
   The file written by this function can be read in parallel with the
   function `hdf5ReadDistributedArray`. The write and read operations
   can use arrays distributed over different numbers of locales.
   

.. function:: proc hdf5ReadDistributedArray(A, filename: string, dsetName: string)

   Read the HDF5 dataset named `dsetName` from the file `filename` into
   the distributed array `A`.  Each locale reads its local portion of
   the array from the file.
   
   This function can read the file that is generated by
   `hdf5WriteDistributedArray`.
   
   Currently only Block and Cyclic distributed arrays are supported.