FormDouble.h

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// Copyright András Vukics 2006–2014. Distributed under the Boost Software License, Version 1.0. (See accompanying file LICENSE.txt)
#ifndef CPPQEDCORE_UTILS_FORMDOUBLE_H_INCLUDED
#define CPPQEDCORE_UTILS_FORMDOUBLE_H_INCLUDED

#include "FormDoubleFwd.h"

#include "Pars.h"

#include <algorithm>
#include <iosfwd>



namespace formdouble {

template<typename T>
std::ostream& operator<<(std::ostream&, const Bound<T>&);

} // formdouble



class FormDouble 
{
public:
  static const int defaultPrecision; 
  

  static       int overallPrecision;


  FormDouble(int precision, int width) : precision_(precision), width_(width) {}
  
  explicit FormDouble(int precision);
  
  template<typename T>
  const formdouble::Bound<T> operator()(const T&) const;


  int getPrecision() const {return precision_;}
  int getWidth    () const {return     width_;}
  
private:
  int precision_;
  int width_;

};



namespace formdouble {

inline int actualPrecision(int precision) {return std::max(FormDouble::defaultPrecision,precision);}


template<typename T>
class Bound 
{
public:
  Bound(const FormDouble& ff, const T& v) : f(ff), val(v) {}

  const FormDouble& f;
  const T& val;

};


int widthPositive(int precision); 
int widthAny     (int precision); 


inline const FormDouble low () {return FormDouble(FormDouble::defaultPrecision/2);} 
inline const FormDouble high() {return FormDouble(FormDouble::defaultPrecision  );} 


inline const FormDouble positive      (int precision) 
{return FormDouble(actualPrecision(precision),widthPositive(actualPrecision(precision)));}

inline const FormDouble zeroAdditional(int precision) 
{return FormDouble(actualPrecision(precision),0);}



class Zero : public FormDouble
{
public:
  Zero() : FormDouble(FormDouble::defaultPrecision) {}
  
  Zero(int precision) : FormDouble(precision,0) {}
  
  operator int() const {return getPrecision();}

};



} // formdouble



namespace parameters {


template<>
class Parameter<formdouble::Zero> : public Parameter<int>
{
public:
  typedef Parameter<int> Base;

  Parameter(const std::string& s, const std::string& d, const formdouble::Zero& v) : Base(s,d,v), v_() {}

  const formdouble::Zero& get() const {return v_=formdouble::Zero(Base::get());}

  formdouble::Zero& get() {return const_cast<formdouble::Zero&>(static_cast<const Parameter*>(this)->get());}

protected:
  void read_v(std::istream& is) {Base::read_v(is); FormDouble::overallPrecision=get();}

private:
  mutable formdouble::Zero v_; // Just a buffer, the actual value is stored in Base

};


} // parameters


#endif // CPPQEDCORE_UTILS_FORMDOUBLE_H_INCLUDED