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MPI_REDUCE & MPI_BARRIER RRS feed

  • Question

  • Hi, i would like to know if it's necessary to add an MPI_BARRIER before MPI_REDUCE or it's done automatically by this last. Thank you answer me
    Friday, January 6, 2012 7:14 AM

All replies

  • Hi,

    MPI_Reduce does not have synchronization semantics and thus there's no implicit barrier within MPI_Reduce. If you want to achieve synchronization with MPI_Reduce, you would have to explicitly issue MPI_Barrier (either before or after MPI_Reduce, depending on the code and the effects you want to achieve)

    Let me know if that answers your question

    Saturday, January 7, 2012 3:37 AM