Generalizing the Buffer Description


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  • Specified in MPI by starting address, datatype, and count, where datatype is:
    -- elementary (all C and Fortran datatypes)
    -- contiguous array of datatypes
    -- strided blocks of datatypes
    -- indexed array of blocks of datatypes
    -- general structure

  • Datatypes are constructed recursively.
  • Specifications of elementary datatypes allows heterogeneous communication.
  • Elimination of length in favor of count is clearer.
  • Specifying application-oriented layout of data allows maximal use of special hardware.



    Up: Sending and Receiving messages Next: Generalizing the Type Previous: The Buffer