Merge pull request #565 from helmholtz-analytics/features/217-reduce_…

…op-docs

Docs fix

heat/core/operations.py

@@ -359,8 +359,9 @@ def __reduce_op(x, partial_op, reduction_op, neutral=None, **kwargs):
         The MPI operator for performing the full reduction based on the results returned by the partial_op function.
 
     neutral: scalar
-        Neutral element for the reduction operation, i.e. an element that does not change the reductions operations
-        result. Required in cases where
+        Neutral element, i.e. an element that does not change the result of the reduction operation. Needed for
+        those cases where 'x.gshape[x.split] < x.comm.rank', that is, the shape of the distributed tensor is such
+        that one or more processes will be left without data.
 
     Returns
     -------