power.hh

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// -*- tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 2 -*-
// vi: set et ts=4 sw=2 sts=2:
#ifndef DUNE_COMMON_POWER_HH
#define DUNE_COMMON_POWER_HH
 
namespace Dune {
 
  template <int m, int p>
  struct StaticPower
  {
    enum { power = (m * StaticPower<m,p-1>::power ) };
  };
 
  template <int m>
  struct StaticPower< m , 0>
  {
    enum { power = 1 };
  };
 
 
   #ifndef DOXYGEN
  template <int p, bool odd = p%2>
  struct PowerImp {};
#endif
 
  template <int p>
  struct Power
  {
    template <typename T>
    static T eval(const T & a)
    {
      return PowerImp<p>::eval(a);
    }
  };
 
#ifndef DOXYGEN
  template <int p>
  struct PowerImp<p,false>
  {
    template <typename T>
    static T eval(const T & a)
    {
      T t = Power<p/2>::eval(a);
      return t*t;
    }
  };
 
  template <int p>
  struct PowerImp<p,true>
  {
    template <typename T>
    static T eval(const T & a)
    {
      return a*Power<p-1>::eval(a);;
    }
  };
 
  template <>
  struct PowerImp<1,true>
  {
    template <typename T>
    static T eval(const T & a)
    {
      return a;
    }
  };
#endif
 
}
 
#endif