Errata: Clarify ordering of accumulate operations with origin == target

[devreal]

Problem

In §11.7.2 of the MPI standard, the text states:

MPI specifies ordering between accumulate operations from one process to the same (or overlapping) memory locations at another process on a per-datatype granularity.

This can be read to not include operations with from one process to itself (origin == target) [1]. However, there is no reason to exclude operations to self from the ordering guarantees (and it seems to be unintentional [2]).

Proposal

By consistently using the terminology of origin and target established in the RMA chapter this ambiguity can be avoided:

MPI specifies ordering between accumulate operations
from an origin process to the same (or overlapping) memory locations at
a target process on a per-datatype granularity.

This proposal fixes another instance where source is used instead of origin.

Changes to the Text

See above.

PR: https://github.com/mpi-forum/mpi-standard/pull/127

Impact on Implementations

None

Impact on Users

It is made clear that accumulate operations from a process to itself are ordered according to the ordering rules outlined in §11.7.2.

References

[1] Merriam Webster: https://www.merriam-webster.com/dictionary/another

Definition of another
1 : different or distinct from the one first considered

[2] RMA WG issue: mpiwg-rma/rma-issues#11

[wesbland]

This passed the first and only vote on in Zurich, Switzerland on 2019-09-07.

[devreal]

This has been fixed with #127, closing.