From a392d409d6dd3d94f6685eaf9fe5941bb0e40c8d Mon Sep 17 00:00:00 2001
From: David Ozog <david.m.ozog@intel.com>
Date: Thu, 11 Jul 2024 16:23:57 -0400
Subject: [PATCH] teams: clarify behavior of split with strides <= 0

---
 content/backmatter.tex               |  4 ++++
 content/shmem_team_split_strided.tex | 11 ++++++++---
 2 files changed, 12 insertions(+), 3 deletions(-)

diff --git a/content/backmatter.tex b/content/backmatter.tex
index 7e6f4a7d..9dc8d17f 100644
--- a/content/backmatter.tex
+++ b/content/backmatter.tex
@@ -703,6 +703,10 @@ \section{Version 1.6}
     additional arguments.
 \ChangelogRef{subsec:shmem_pcontrol}
 %
+\item Clarified the behavior of \FUNC{shmem\_team\_split\_strided} when the
+    stride argument is 0 or negative.
+\ChangelogRef{subsec:shmem_team_split_strided}
+%
 \end{itemize}
 
 \section{Version 1.5}
diff --git a/content/shmem_team_split_strided.tex b/content/shmem_team_split_strided.tex
index 990f6220..08969792 100644
--- a/content/shmem_team_split_strided.tex
+++ b/content/shmem_team_split_strided.tex
@@ -50,10 +50,15 @@
   i \in \mathbb{Z}_{size-1}
 \end{equation*}
 where $\mathbb{Z}$ is the set of natural numbers ($0, 1, \dots$), $N$ is the
-number of \acp{PE} in the parent team and $size$ is a positive number indicating
-the number of \acp{PE} in the new team. The index $i$ specifies the number of
-the given PE in the new team. Thus, \acp{PE} in the new team remain in the same
+number of \acp{PE} in the parent team, $size$ is a positive number indicating
+the number of \acp{PE} in the new team, and $stride$ is an integer.
+The index $i$ specifies the number of the given PE in the new team.
+When $stride$ is greater than zero, PEs in the new team remain in the same
 relative order as in the parent team.
+When $stride$ is less than zero, PEs in the new team are in \textit{reverse}
+relative order with respect to the parent team.
+If a $stride$ value equal to 0 is passed to \FUNC{shmem\_team\_split\_strided},
+then the $size$ argument passed must be 1, or the behavior is undefined.
 
 This routine must be called by all \acp{PE} in the parent team.
 All \acp{PE} must provide the same values for the \ac{PE} triplet.