ENH: UList shuffle function to randomly reorder a list.

src/OpenFOAM/containers/Lists/UList/UList.C

@@ -145,6 +145,13 @@ void Foam::stableSort(UList<T>& a, const Cmp& cmp)
 }
 
 
+template<class T>
+void Foam::shuffle(UList<T>& a)
+{
+    std::random_shuffle(a.begin(), a.end());
+}
+
+
 // * * * * * * * * * * * * * * * Member Operators  * * * * * * * * * * * * * //
 
 template<class T>

src/OpenFOAM/containers/Lists/UList/UList.H

@@ -344,6 +344,9 @@ void stableSort(UList<T>&);
 template<class T, class Cmp>
 void stableSort(UList<T>&, const Cmp&);
 
+template<class T>
+void shuffle(UList<T>&);
+
 // Reverse the first n elements of the list
 template<class T>
 inline void reverse(UList<T>&, const label n);