scale.hh

/* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * */
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/*   This file is part of the C++-library RFFGen.                              */
/*   Copyright 2015 Lars Lubkoll                                               */
/*                                                                             */
/*   RFFGen is free software: you can redistribute it and/or modify            */
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#ifndef RFFGEN_MATHEMATICAL_OPERATIONS_SCALE_HH
#define RFFGEN_MATHEMATICAL_OPERATIONS_SCALE_HH

#include <type_traits>
#include <utility>

#include "../Util/base.hh"
#include "../Util/derivativeWrappers.hh"
#include "../Util/indexedType.hh"

namespace RFFGen
{
  template <class> struct Chainer;
  namespace MathematicalOperations
  {
    template <class> struct FunctionConceptCheck;
    template <class F, class = FunctionConceptCheck<F> >
    struct Scale : Base , Chainer< Scale< F , FunctionConceptCheck<F> > >
    {
      using Chainer< Scale< F , FunctionConceptCheck<F> > >::operator();
      Scale() = default;

      template <class InitF>
      Scale(double a_, const InitF& f_) : a(a_), f(f_)
      {
        updateResultOfD0();
      }

      template <class Arg>
      void update(Arg const& arg)
      {
        f.update(arg);
        updateResultOfD0();
      }

      template <int index, class Arg>
      void updateVariable(const Arg& x)
      {
        f.template updateVariable<index>(x);
      }

      const auto& d0() const noexcept
      {
        return resultOfD0;
      }

        template < int idx , class Arg ,
                 class IndexedArg = IndexedType<Arg,idx> ,
                 class = std::enable_if_t< D1<F,IndexedArg>::present> >
      auto d1(Arg const& dx) const
      {
        return a * f.template d1<idx>(dx);
      }

        template < int idx , int idy , class ArgX , class ArgY ,
                 class IndexedArgX = IndexedType<ArgX,idx> ,
                 class IndexedArgY = IndexedType<ArgY,idy> ,
                 class = std::enable_if_t< D2<F,IndexedArgX,IndexedArgY>::present> >
      auto d2(ArgX const& dx, ArgY const& dy) const
      {
        return a * f.template d2<idx,idy>(dx,dy);
      }

      template < int idx , int idy , int idz , class ArgX , class ArgY , class ArgZ ,
                 class IndexedArgX = IndexedType<ArgX,idx> ,
                 class IndexedArgY = IndexedType<ArgY,idy> ,
                 class IndexedArgZ = IndexedType<ArgZ,idz> ,
                 class = std::enable_if_t< D3<F,IndexedArgX,IndexedArgY,IndexedArgZ>::present > >
      auto d3(ArgX const& dx, ArgY const& dy, ArgZ const& dz) const
      {
        return a * f.template d3<idx,idy,idz>(dx,dy,dz);
      }

    private:
      void updateResultOfD0()
      {
        resultOfD0 = a * f.d0();
      }

      double a = 1.;
      F f;
      std::remove_const_t<std::remove_reference_t<decltype(std::declval<F>().d0())> > resultOfD0;
    };
  }
}

#endif // RFFGEN_MATHEMATICAL_OPERATIONS_SCALE_HH