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In addition to
the point to point routines
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discussed so far,
MPI has many routines
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for collective communications.
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These are
typically of the type one – to –
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many , many
– to – one and many – to –
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many .
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All the collective routines are blocking .
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Most frequently
used routines are BCAST,
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REDUCE,
SCATTER, ALLTOALL .
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