add note about NEP13/18 not applying

SciTools · Nov 23, 2022 · 2be06cb · 2be06cb
1 parent e7451ca
commit 2be06cb
Showing 1 changed file with 4 additions and 0 deletions.
diff --git a/lib/iris/analysis/__init__.py b/lib/iris/analysis/__init__.py
@@ -1590,6 +1590,10 @@ def _rms(array, axis, **kwargs):
 
 
 def _lazy_rms(array, axis, **kwargs):
+    # Note that, since we specifically need the ma version of average to handle
+    # weights correctly with masked data, we cannot rely on NEP13/18 and need
+    # to implement a separate lazy RMS function.
+
     rval = da.sqrt(da.ma.average(array**2, axis=axis, **kwargs))
 
     return rval