Trilinos
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Looking at the packages/muelu/doc/Tutorial/src/laplace2d.cpp, there are several comm->barrier() commands sprinkled throughout. And at lines 383, 384, 385, 3 of them in a row. Wouldn't one call be sufficient? And what is a good rule of thumb to know when to call a barrier? Thanks in advance for any guidance and clarification.
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One barrier is sufficient, and adding more isn't useful. At one time long ago, maybe that wasn't the case. Barriers are useful if you want to synchronize all MPI ranks in a communicator. In MueLu examples, we do that to ensure all ranks have finished a section of code that's being timed. |
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ok, great! Thanks for the speedy response! |
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One barrier is sufficient, and adding more isn't useful. At one time long ago, maybe that wasn't the case.
Barriers are useful if you want to synchronize all MPI ranks in a communicator. In MueLu examples, we do that to ensure all ranks have finished a section of code that's being timed.