Restrict utilities to integer types (#2264)

include/alpaka/core/Utility.hpp

@@ -1,4 +1,4 @@
-/* Copyright 2022 Benjamin Worpitz, René Widera, Bernhard Manfred Gruber, Jan Stephan
+/* Copyright 2024 Benjamin Worpitz, René Widera, Bernhard Manfred Gruber, Jan Stephan, Andrea Bocci
  * SPDX-License-Identifier: MPL-2.0
  */
 #pragma once
@@ -23,14 +23,14 @@ namespace alpaka::core
 #endif
 
     /// Returns the ceiling of a / b, as integer.
-    template<typename Integral>
+    template<typename Integral, typename = std::enable_if_t<std::is_integral_v<Integral>>>
     [[nodiscard]] ALPAKA_FN_HOST_ACC constexpr auto divCeil(Integral a, Integral b) -> Integral
     {
         return (a + b - 1) / b;
     }
 
     /// Computes the nth power of base, in integers.
-    template<typename Integral>
+    template<typename Integral, typename = std::enable_if_t<std::is_integral_v<Integral>>>
     [[nodiscard]] ALPAKA_FN_HOST_ACC constexpr auto intPow(Integral base, Integral n) -> Integral
     {
         if(n == 0)
@@ -42,7 +42,7 @@ namespace alpaka::core
     }
 
     /// Computes the floor of the nth root of value, in integers.
-    template<typename Integral>
+    template<typename Integral, typename = std::enable_if_t<std::is_integral_v<Integral>>>
     [[nodiscard]] ALPAKA_FN_HOST_ACC constexpr auto nthRootFloor(Integral value, Integral n) -> Integral
     {
         // adapted from: https://en.wikipedia.org/wiki/Integer_square_root
@@ -58,4 +58,5 @@ namespace alpaka::core
         }
         return L;
     }
+
 } // namespace alpaka::core