ceph/src/boost/libs/math/include/boost/math/constants/info.hpp

   1 //  Copyright John Maddock 2010.
   2 //  Use, modification and distribution are subject to the
   3 //  Boost Software License, Version 1.0. (See accompanying file
   4 //  LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
   5
   6 #ifdef _MSC_VER
   7 #  pragma once
   8 #endif
   9
  10 #ifndef BOOST_MATH_CONSTANTS_INFO_INCLUDED
  11 #define BOOST_MATH_CONSTANTS_INFO_INCLUDED
  12
  13 #include <boost/math/constants/constants.hpp>
  14 #include <iostream>
  15 #include <iomanip>
  16 #include <typeinfo>
  17
  18 namespace boost{ namespace math{ namespace constants{
  19
  20    namespace detail{
  21
  22       template <class T>
  23       const char* nameof(BOOST_MATH_EXPLICIT_TEMPLATE_TYPE_SPEC(T))
  24       {
  25          return typeid(T).name();
  26       }
  27       template <>
  28       const char* nameof<float>(BOOST_MATH_EXPLICIT_TEMPLATE_TYPE_SPEC(float))
  29       {
  30          return "float";
  31       }
  32       template <>
  33       const char* nameof<double>(BOOST_MATH_EXPLICIT_TEMPLATE_TYPE_SPEC(double))
  34       {
  35          return "double";
  36       }
  37       template <>
  38       const char* nameof<long double>(BOOST_MATH_EXPLICIT_TEMPLATE_TYPE_SPEC(long double))
  39       {
  40          return "long double";
  41       }
  42
  43    }
  44
  45 template <class T, class Policy>
  46 void print_info_on_type(std::ostream& os = std::cout BOOST_MATH_APPEND_EXPLICIT_TEMPLATE_TYPE_SPEC(T) BOOST_MATH_APPEND_EXPLICIT_TEMPLATE_TYPE_SPEC(Policy))
  47 {
  48    using detail::nameof;
  49 #ifdef BOOST_MSVC
  50 #pragma warning(push)
  51 #pragma warning(disable:4127)
  52 #endif
  53    os <<
  54       "Information on the Implementation and Handling of \n"
  55       "Mathematical Constants for Type " << nameof<T>() <<
  56       "\n\n"
  57       "Checking for std::numeric_limits<" << nameof<T>() << "> specialisation: " <<
  58       (std::numeric_limits<T>::is_specialized ? "yes" : "no") << std::endl;
  59    if(std::numeric_limits<T>::is_specialized)
  60    {
  61       os <<
  62          "std::numeric_limits<" << nameof<T>() << ">::digits reports that the radix is " << std::numeric_limits<T>::radix << ".\n";
  63       if (std::numeric_limits<T>::radix == 2)
  64       {
  65       os <<
  66          "std::numeric_limits<" << nameof<T>() << ">::digits reports that the precision is \n" << std::numeric_limits<T>::digits << " binary digits.\n";
  67       }
  68       else if (std::numeric_limits<T>::radix == 10)
  69       {
  70          os <<
  71          "std::numeric_limits<" << nameof<T>() << ">::digits reports that the precision is \n" << std::numeric_limits<T>::digits10 << " decimal digits.\n";
  72          os <<
  73          "std::numeric_limits<" << nameof<T>() << ">::digits reports that the precision is \n"
  74          << std::numeric_limits<T>::digits * 1000L /301L << " binary digits.\n";  // divide by log2(10) - about 3 bits per decimal digit.
  75       }
  76       else
  77       {
  78         os << "Unknown radix = " << std::numeric_limits<T>::radix << "\n";
  79       }
  80    }
  81    typedef typename boost::math::policies::precision<T, Policy>::type precision_type;
  82    if(precision_type::value)
  83    {
  84       if (std::numeric_limits<T>::radix == 2)
  85       {
  86        os <<
  87        "boost::math::policies::precision<" << nameof<T>() << ", " << nameof<Policy>() << " reports that the compile time precision is \n" << precision_type::value << " binary digits.\n";
  88       }
  89       else if (std::numeric_limits<T>::radix == 10)
  90       {
  91          os <<
  92          "boost::math::policies::precision<" << nameof<T>() << ", " << nameof<Policy>() << " reports that the compile time precision is \n" << precision_type::value << " binary digits.\n";
  93       }
  94       else
  95       {
  96         os << "Unknown radix = " << std::numeric_limits<T>::radix <<  "\n";
  97       }
  98    }
  99    else
 100    {
 101       os <<
 102          "boost::math::policies::precision<" << nameof<T>() << ", Policy> \n"
 103          "reports that there is no compile type precision available.\n"
 104          "boost::math::tools::digits<" << nameof<T>() << ">() \n"
 105          "reports that the current runtime precision is \n" <<
 106          boost::math::tools::digits<T>() << " binary digits.\n";
 107    }
 108
 109    typedef typename construction_traits<T, Policy>::type construction_type;
 110
 111    switch(construction_type::value)
 112    {
 113    case 0:
 114       os <<
 115          "No compile time precision is available, the construction method \n"
 116          "will be decided at runtime and results will not be cached \n"
 117          "- this may lead to poor runtime performance.\n"
 118          "Current runtime precision indicates that\n";
 119       if(boost::math::tools::digits<T>() > max_string_digits)
 120       {
 121          os << "the constant will be recalculated on each call.\n";
 122       }
 123       else
 124       {
 125          os << "the constant will be constructed from a string on each call.\n";
 126       }
 127       break;
 128    case 1:
 129       os <<
 130          "The constant will be constructed from a float.\n";
 131       break;
 132    case 2:
 133       os <<
 134          "The constant will be constructed from a double.\n";
 135       break;
 136    case 3:
 137       os <<
 138          "The constant will be constructed from a long double.\n";
 139       break;
 140    case 4:
 141       os <<
 142          "The constant will be constructed from a string (and the result cached).\n";
 143       break;
 144    default:
 145       os <<
 146          "The constant will be calculated (and the result cached).\n";
 147       break;
 148    }
 149    os << std::endl;
 150 #ifdef BOOST_MSVC
 151 #pragma warning(pop)
 152 #endif
 153 }
 154
 155 template <class T>
 156 void print_info_on_type(std::ostream& os = std::cout BOOST_MATH_APPEND_EXPLICIT_TEMPLATE_TYPE_SPEC(T))
 157 {
 158    print_info_on_type<T, boost::math::policies::policy<> >(os);
 159 }
 160
 161 }}} // namespaces
 162
 163 #endif // BOOST_MATH_CONSTANTS_INFO_INCLUDED