maximum_norm.h

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#ifndef MATHTOOLS_MAXIMUM_NORM_H
#define MATHTOOLS_MAXIMUM_NORM_H

#include "norm.h"
#include <algorithm>

namespace math {
namespace internal {

template<typename COORD_ITERATOR>
auto MaximumFunc_value(COORD_ITERATOR begin, COORD_ITERATOR end) -> decltype(typeHelper(*begin))
{
  return *std::max_element(begin, end);
}

template<std::size_t N, typename COORD_TYPE>
struct MaximumFuncArity
{
  static typename NumTraits<COORD_TYPE>::Real value(const COORD_TYPE* coordPtr)
  {
    return std::max(*(coordPtr + N - 1), MaximumFuncArity<N - 1, COORD_TYPE>::value(coordPtr));
  }
};

template<typename COORD_TYPE>
struct MaximumFuncArity<1, COORD_TYPE>
{
  static typename NumTraits<COORD_TYPE>::Real value(const COORD_TYPE* coordPtr)
  { return *coordPtr; }
};

struct MaximumFunc
{
  template<typename COORD_ITERATOR>
  static auto fromRange(COORD_ITERATOR begin, COORD_ITERATOR end) -> decltype(typeHelper(*begin))
  { return MaximumFunc_value(begin, end); }

  template<std::size_t N, typename COORD_TYPE>
  static typename NumTraits<COORD_TYPE>::Real fromPtr(const COORD_TYPE* coordPtr)
  { return MaximumFuncArity<N, COORD_TYPE>::value(coordPtr); }
};

template<> struct NormTraits<internal::MaximumFunc>
{
  typedef ArityNormSpecializationTag NormCategory;
};

} // namespace internal

typedef Norm<internal::MaximumFunc> MaximumNorm;

} // namespace math

#endif // MATHTOOLS_MAXIMUM_NORM_H