Merge branch 'fix/factorial' into 'master'

[math] Use integer type in Factorial

See merge request !1045

CHANGELOG.md

@@ -2,6 +2,8 @@
 
 - Add `pragma omp simd` annotations in the LoopSIMD class to improve compiler optimizations
 
+- deprecate Factorial in common/math.hh (use factorial function)
+
 ## Build System
 
 - Remove the variable `DUNE_DEFAULT_LIBS`
@@ -21,7 +23,6 @@
 
 - Remove deprecated cmake function overload `target_link_libraries`
 
-
 # Release 2.8
 
 - Set minimal required CMake version in cmake to >= 3.13.

dune/common/math.hh

@@ -86,19 +86,20 @@ namespace Dune
   }
 
   //! Calculates the factorial of m at compile time
+  //! \deprecated Will be removed after release 2.9
   template <int m>
   struct Factorial
   {
     //! factorial stores m!
-    enum { factorial = m * Factorial<m-1>::factorial };
+    static constexpr int factorial = m * Factorial<m-1>::factorial;
   };
 
   //! end of recursion of factorial via specialization
   template <>
-  struct Factorial<0>
+  struct [[deprecated("Use function factorial instead! Will be removed after Dune 2.9")]] Factorial<0>
   {
     // 0! = 1
-    enum { factorial = 1 };
+    static constexpr int factorial = 1;
   };
 
 

dune/common/test/mathtest.cc

@@ -26,12 +26,14 @@ auto testStaticFactorial (std::integral_constant<T, k> _k = {}) -> TestSuite
 {
   TestSuite t;
 
-  std::cout << "test static factorial\n{";
+  std::cout << "test factorial\n{";
 
   forEach(integralRange(_k), [&](auto _i) {
-    auto value = Dune::factorial(_i);
 
-    t.check(decltype(value)::value == Dune::Factorial<decltype(_i)::value>::factorial);
+    const auto value = Dune::factorial(_i);
+    const auto control = _i() == 0 ? 1 : _i() * Dune::factorial(_i() - 1);
+
+    t.check( value() == control );
 
     std::cout<< ' ' << value() << ',';
   });
@@ -46,17 +48,16 @@ auto testStaticBinomial (std::integral_constant<T, k> _k = {}) -> TestSuite
 {
   TestSuite t;
 
-  std::cout << "test static binomial\n";
+  std::cout << "test binomial\n";
 
   forEach(integralRange(_k), [&](auto _i) {
     std::cout << "{";
     forEach(integralRange(next(_i)), [&](auto _j) {
-      const auto value = Dune::binomial(_i,_j);
 
-      auto control = Dune::Factorial<decltype(_i)::value>::factorial
-                     / Dune::Factorial<decltype(_j)::value>::factorial
-                     / Dune::Factorial<decltype(_i)::value - decltype(_j)::value>::factorial;
-      t.check(decltype(value)::value == control);
+      const auto value = Dune::binomial(_i, _j);
+      const auto control = Dune::factorial(_i) / ( Dune::factorial(_j) * Dune::factorial(_i() - _j()) );
+
+      t.check( value() == control );
 
       std::cout<< ' ' << value() << ',';
     });