Merge pull request #16 from davidozog/pr/associativity_note

reductions: add note about FP associativity

content/shmem_reductions.tex

@@ -376,6 +376,18 @@ \subsubsubsection{PROD}
     Zero on successful local completion. Nonzero otherwise.
 }
 
+\apinotes{
+    The binary operations performed by \openshmem reductions are intended to be
+    associative and commutative.
+    However, floating point arithmetic is not associative or commutative due to
+    the inherent inaccuracies of floating-point representations caused by
+    rounding errors and finite precision.
+    This can lead to variations in the result of \openshmem arithmetic
+    reduction operations on floating-point datatypes, including NaN values.
+    A future version of the \openshmem specification may clarify the behavior
+    of reductions on floating point datatypes.
+}
+
 \begin{apiexamples}
 
 \apicexample