Page tree

The license could not be verified: License Certificate has expired!

Versions Compared

Key

  • This line was added.
  • This line was removed.
  • Formatting was changed.

...

    • Create or open a Parallel HDF5 file with a collective call to:

       

      H5D_CREATE
      H5D_OPEN

       

    • Obtain a copy of the file transfer property list and set it to use collective or independent I/O.
      Do this by first passing a data transfer property list class type to: 
      H5P_CREATE

      Then set the data transfer mode to either use independent I/O access or to use collective I/O, with a call to:

      H5PsetH5P_dxpl_mpio (C) / h5pset_dxpl_mpio_f (F90)SET_DXPL_MPIO

      Following are the parameters required by this call:

      C:
          herr_t H5Pset_dxpl_mpio (hid_t dxpl_id, H5FD_mpio_xfer_t  xfer_mode )
               dxpl_id    IN: Data transfer property list identifier
               xfer_mode  IN: Transfer mode:
                              H5FD_MPIO_INDEPENDENT - use independent I/O access
                                                      (default)
                              H5FD_MPIO_COLLECTIVE  - use collective I/O access
      
      F90:
         h5pset_dxpl_mpi_f (prp_id, data_xfer_mode, hdferr)
               prp_id         IN: Property List Identifer (INTEGER (HID_T))
               data_xfer_mode IN: Data transfer mode  (INTEGER)
                                    H5FD_MPIO_INDEPENDENT_F (0)
                                    H5FD_MPIO_COLLECTIVE_F (1)
               hdferr         IN: Error code  (INTEGER)
      

       

    • Access the dataset with the defined transfer property list.

      All processes that have opened a dataset may do collective I/O. Each process may do an independent and arbitrary number of data I/O access calls, using:

      H5D_WRITE
      H5D_READ

      If a dataset is unlimited, you can extend it with a collective call to:

      H5D_EXTEND

...