comparison DEPENDENCIES/generic/include/boost/math/tools/fraction.hpp @ 16:2665513ce2d3

Add boost headers

+//  (C) Copyright John Maddock 2005-2006.
+//  Use, modification and distribution are subject to the
+//  Boost Software License, Version 1.0. (See accompanying file
+//  LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+
+#ifndef BOOST_MATH_TOOLS_FRACTION_INCLUDED
+#define BOOST_MATH_TOOLS_FRACTION_INCLUDED
+
+#ifdef _MSC_VER
+#pragma once
+#endif
+
+#include <boost/config/no_tr1/cmath.hpp>
+#include <boost/cstdint.hpp>
+#include <boost/type_traits/integral_constant.hpp>
+#include <boost/mpl/if.hpp>
+#include <boost/math/tools/precision.hpp>
+
+namespace boost{ namespace math{ namespace tools{
+
+namespace detail
+{
+
+   template <class T>
+   struct is_pair : public boost::false_type{};
+
+   template <class T, class U>
+   struct is_pair<std::pair<T,U> > : public boost::true_type{};
+
+   template <class Gen>
+   struct fraction_traits_simple
+   {
+       typedef typename Gen::result_type result_type;
+       typedef typename Gen::result_type value_type;
+
+       static result_type a(const value_type&)
+       {
+          return 1;
+       }
+       static result_type b(const value_type& v)
+       {
+          return v;
+       }
+   };
+
+   template <class Gen>
+   struct fraction_traits_pair
+   {
+       typedef typename Gen::result_type value_type;
+       typedef typename value_type::first_type result_type;
+
+       static result_type a(const value_type& v)
+       {
+          return v.first;
+       }
+       static result_type b(const value_type& v)
+       {
+          return v.second;
+       }
+   };
+
+   template <class Gen>
+   struct fraction_traits
+       : public boost::mpl::if_c<
+         is_pair<typename Gen::result_type>::value,
+         fraction_traits_pair<Gen>,
+         fraction_traits_simple<Gen> >::type
+   {
+   };
+
+} // namespace detail
+
+//
+// continued_fraction_b
+// Evaluates:
+//
+// b0 +       a1
+//      ---------------
+//      b1 +     a2
+//           ----------
+//           b2 +   a3
+//                -----
+//                b3 + ...
+//
+// Note that the first a0 returned by generator Gen is disarded.
+//
+template <class Gen, class U>
+inline typename detail::fraction_traits<Gen>::result_type continued_fraction_b(Gen& g, const U& factor, boost::uintmax_t& max_terms)
+{
+   BOOST_MATH_STD_USING // ADL of std names
+
+   typedef detail::fraction_traits<Gen> traits;
+   typedef typename traits::result_type result_type;
+   typedef typename traits::value_type value_type;
+
+   result_type tiny = tools::min_value<result_type>();
+
+   value_type v = g();
+
+   result_type f, C, D, delta;
+   f = traits::b(v);
+   if(f == 0)
+      f = tiny;
+   C = f;
+   D = 0;
+
+   boost::uintmax_t counter(max_terms);
+
+   do{
+      v = g();
+      D = traits::b(v) + traits::a(v) * D;
+      if(D == 0)
+         D = tiny;
+      C = traits::b(v) + traits::a(v) / C;
+      if(C == 0)
+         C = tiny;
+      D = 1/D;
+      delta = C*D;
+      f = f * delta;
+   }while((fabs(delta - 1) > factor) && --counter);
+
+   max_terms = max_terms - counter;
+
+   return f;
+}
+
+template <class Gen, class U>
+inline typename detail::fraction_traits<Gen>::result_type continued_fraction_b(Gen& g, const U& factor)
+{
+   boost::uintmax_t max_terms = (std::numeric_limits<boost::uintmax_t>::max)();
+   return continued_fraction_b(g, factor, max_terms);
+}
+
+template <class Gen>
+inline typename detail::fraction_traits<Gen>::result_type continued_fraction_b(Gen& g, int bits)
+{
+   BOOST_MATH_STD_USING // ADL of std names
+
+   typedef detail::fraction_traits<Gen> traits;
+   typedef typename traits::result_type result_type;
+
+   result_type factor = ldexp(1.0f, 1 - bits); // 1 / pow(result_type(2), bits);
+   boost::uintmax_t max_terms = (std::numeric_limits<boost::uintmax_t>::max)();
+   return continued_fraction_b(g, factor, max_terms);
+}
+
+template <class Gen>
+inline typename detail::fraction_traits<Gen>::result_type continued_fraction_b(Gen& g, int bits, boost::uintmax_t& max_terms)
+{
+   BOOST_MATH_STD_USING // ADL of std names
+
+   typedef detail::fraction_traits<Gen> traits;
+   typedef typename traits::result_type result_type;
+
+   result_type factor = ldexp(1.0f, 1 - bits); // 1 / pow(result_type(2), bits);
+   return continued_fraction_b(g, factor, max_terms);
+}
+
+//
+// continued_fraction_a
+// Evaluates:
+//
+//            a1
+//      ---------------
+//      b1 +     a2
+//           ----------
+//           b2 +   a3
+//                -----
+//                b3 + ...
+//
+// Note that the first a1 and b1 returned by generator Gen are both used.
+//
+template <class Gen, class U>
+inline typename detail::fraction_traits<Gen>::result_type continued_fraction_a(Gen& g, const U& factor, boost::uintmax_t& max_terms)
+{
+   BOOST_MATH_STD_USING // ADL of std names
+
+   typedef detail::fraction_traits<Gen> traits;
+   typedef typename traits::result_type result_type;
+   typedef typename traits::value_type value_type;
+
+   result_type tiny = tools::min_value<result_type>();
+
+   value_type v = g();
+
+   result_type f, C, D, delta, a0;
+   f = traits::b(v);
+   a0 = traits::a(v);
+   if(f == 0)
+      f = tiny;
+   C = f;
+   D = 0;
+
+   boost::uintmax_t counter(max_terms);
+
+   do{
+      v = g();
+      D = traits::b(v) + traits::a(v) * D;
+      if(D == 0)
+         D = tiny;
+      C = traits::b(v) + traits::a(v) / C;
+      if(C == 0)
+         C = tiny;
+      D = 1/D;
+      delta = C*D;
+      f = f * delta;
+   }while((fabs(delta - 1) > factor) && --counter);
+
+   max_terms = max_terms - counter;
+
+   return a0/f;
+}
+
+template <class Gen, class U>
+inline typename detail::fraction_traits<Gen>::result_type continued_fraction_a(Gen& g, const U& factor)
+{
+   boost::uintmax_t max_iter = (std::numeric_limits<boost::uintmax_t>::max)();
+   return continued_fraction_a(g, factor, max_iter);
+}
+
+template <class Gen>
+inline typename detail::fraction_traits<Gen>::result_type continued_fraction_a(Gen& g, int bits)
+{
+   BOOST_MATH_STD_USING // ADL of std names
+
+   typedef detail::fraction_traits<Gen> traits;
+   typedef typename traits::result_type result_type;
+
+   result_type factor = ldexp(1.0f, 1-bits); // 1 / pow(result_type(2), bits);
+   boost::uintmax_t max_iter = (std::numeric_limits<boost::uintmax_t>::max)();
+
+   return continued_fraction_a(g, factor, max_iter);
+}
+
+template <class Gen>
+inline typename detail::fraction_traits<Gen>::result_type continued_fraction_a(Gen& g, int bits, boost::uintmax_t& max_terms)
+{
+   BOOST_MATH_STD_USING // ADL of std names
+
+   typedef detail::fraction_traits<Gen> traits;
+   typedef typename traits::result_type result_type;
+
+   result_type factor = ldexp(1.0f, 1-bits); // 1 / pow(result_type(2), bits);
+   return continued_fraction_a(g, factor, max_terms);
+}
+
+} // namespace tools
+} // namespace math
+} // namespace boost
+
+#endif // BOOST_MATH_TOOLS_FRACTION_INCLUDED
+