From f5638a3e29c0e4b7b18836163916cb15945b47f1 Mon Sep 17 00:00:00 2001
From: Thomas Gibson <gibsonthomas1120@hotmail.com>
Date: Sat, 13 Nov 2021 07:52:18 -0600
Subject: [PATCH] Add short comments concerning rank-local trace pairs
---
grudge/trace_pair.py | 11 +++++++++++
1 file changed, 11 insertions(+)
diff --git a/grudge/trace_pair.py b/grudge/trace_pair.py
index f8a32a94..3dbca276 100644
--- a/grudge/trace_pair.py
+++ b/grudge/trace_pair.py
@@ -220,6 +220,14 @@ def interior_trace_pair(dcoll: DiscretizationCollection, vec) -> TracePair:
*dcoll* with a discretization tag specified by *discr_tag*.
This does not include interior faces on different MPI ranks.
+ For certain applications, it may be useful to distinguish between
+ rank-local and cross-rank trace pairs. For example, avoiding unnecessary
+ communication of derived quantities (i.e. temperature) on partition
+ boundaries by computing them directly. Having the ability for
+ user applications to distinguish between rank-local and cross-rank
+ contributions can also help enable overlapping communication with
+ computation.
+
:arg vec: a :class:`~meshmode.dof_array.DOFArray` or object array of
:class:`~meshmode.dof_array.DOFArray`\ s.
:returns: a :class:`TracePair` object.
@@ -244,6 +252,9 @@ def interior_trace_pairs(dcoll: DiscretizationCollection, vec) -> list:
defined on the interior faces of *dcoll* and any faces connected to a
parallel boundary.
+ Note that :func:`interior_trace_pair` provides the rank-local contributions
+ if those are needed in isolation.
+
:arg vec: a :class:`~meshmode.dof_array.DOFArray` or object array of
:class:`~meshmode.dof_array.DOFArray`\ s.
:returns: a :class:`list` of :class:`TracePair` objects.
--
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