make max and min work with user-defined casts

src/amdis/common/Math.hpp

@@ -43,7 +43,8 @@ namespace AMDiS
     template <class T0, class T1>
     constexpr auto min(T0 a, T1 b)
     {
-      return a < b ? a : b;
+      using T = std::conditional_t<(sizeof(T0)>sizeof(T1)),T0,T1>;
+      return a < b ? T(a) : T(b);
     }
 
     template <class T0>
@@ -62,12 +63,14 @@ namespace AMDiS
 
 
     /// Implementation of the maximum of values \f$ max(a,b)\f$ of any type
-    /// supporting the `>` relation.
+    /// supporting the `<` relation.
     /// @{
+
     template <class T0, class T1>
     constexpr auto max(T0 a, T1 b)
     {
-      return a < b ? b : a;
+      using T = std::conditional_t<(sizeof(T0)>sizeof(T1)),T0,T1>;
+      return a < b ? T(b) : T(a);
     }
 
     template <class T0>