fnmath.hpp~

浮点数基本运算 浮点数的基本运算主要有四则运算、符号处理、大小比较

// Float number math implementation -*- C++ -*-

// Copyright (C) 2005 Ben T. Bear
//
// This file is published under GNU GPL 2.0. See more in "copy.hpp".

// #include "copy.hpp"

#ifndef __bt2il_fn_math_hpp
#define __bt2il_fn_math_hpp

#include "fn.hpp"
#include "fnexp.hpp"

namespace btil
{
  namespace fn
  {
    template <typename a>
    struct sqrt;

    template <int n>
    struct factorial;

    template <typename x, typename y>
    struct pow;

    template <typename x, int n>
    struct pow_n;


    
    
    template <typename a>
    struct sqrt
    {
      struct value
      {
	static const double f_val = __sqrt<a>::f_val;
      };
    };



    template <int n>
    struct factorial
    {
      static const double f_val = __factorial<n>::f_val;
    };




    template <typename x, typename y>
    struct pow
    {
      struct __x
      {
	static const double f_val = y::f_val * ln<x>::value::f_val;
      };

      struct value
      {
	static const double f_val = exp<__x>::value::f_val;
      };
    };



    template <typename x, int n>
    struct __pow_n_p
    {
      static const double e = __pow_n_p<x, n/2>::f_val;
      static const double b = (n % 2 == 0) ? 1.0 : x::f_val;
      static const double f_val = e * e * b;
    };

    template <typename x>
    struct __pow_n_p<x, 0>
    {
      static const double f_val = 1.0;
    };

    template <bool neg, typename x, int n>
    struct __pow_n_bool;

    template <typename x, int n>
    struct __pow_n_bool<true, x, n>
    {
      static const double f_val = 1.0 / __pow_n_p<x, -n>::f_val;
    };

    template <typename x, int n>
    struct __pow_n_bool<false, x, n>
    {
      static const double f_val = __pow_n_p<x, n>::f_val;
    };

    template <typename x, int n>
    struct __pow_n
    {
      static const double f_val = __pow_n_bool<(n < 0), x, n>::f_val;
    };


    template <typename x, int n>
    struct pow_n
    {
      struct value
      {
	static const double f_val = __pow_n<x, n>::f_val;
      };
    };
  }
}

#endif