Notes on Message Passing Program

• Use of ghost rows

• Receive does not transfer data, send does

  • unlike SAS which is usually receiver-initiated (load fetches data)

• Communication done at beginning of iteration, so no asynchrony

• Communication in whole rows, not element at a time

• Core similar, but indices/bounds in local rather than global space

• Synchronization through sends and receives

  • Update of global diff and event synch for done condition
  • Could implement locks and barriers with messages

• REDUCE and BROADCAST simplify code

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