source: NonGTP/Boost/boost/numeric/interval/detail/division.hpp @ 857

Revision 857, 7.5 KB checked in by igarcia, 19 years ago (diff)
Line 
1/* Boost interval/detail/division.hpp file
2 *
3 * Copyright 2003 Guillaume Melquiond, Sylvain Pion
4 *
5 * Distributed under the Boost Software License, Version 1.0.
6 * (See accompanying file LICENSE_1_0.txt or
7 * copy at http://www.boost.org/LICENSE_1_0.txt)
8 */
9
10#ifndef BOOST_NUMERIC_INTERVAL_DETAIL_DIVISION_HPP
11#define BOOST_NUMERIC_INTERVAL_DETAIL_DIVISION_HPP
12
13#include <boost/numeric/interval/detail/interval_prototype.hpp>
14#include <boost/numeric/interval/detail/bugs.hpp>
15#include <boost/numeric/interval/detail/test_input.hpp>
16#include <boost/numeric/interval/rounded_arith.hpp>
17#include <algorithm>
18
19namespace boost {
20namespace numeric {
21namespace interval_lib {
22namespace detail {
23
24template<class T, class Policies> inline
25interval<T, Policies> div_non_zero(const interval<T, Policies>& x,
26                                   const interval<T, Policies>& y)
27{
28  // assert(!in_zero(y));
29  typename Policies::rounding rnd;
30  typedef interval<T, Policies> I;
31  const T& xl = x.lower();
32  const T& xu = x.upper();
33  const T& yl = y.lower();
34  const T& yu = y.upper();
35  if (::boost::numeric::interval_lib::user::is_neg(xu))
36    if (::boost::numeric::interval_lib::user::is_neg(yu))
37      return I(rnd.div_down(xu, yl), rnd.div_up(xl, yu), true);
38    else
39      return I(rnd.div_down(xl, yl), rnd.div_up(xu, yu), true);
40  else if (::boost::numeric::interval_lib::user::is_neg(xl))
41    if (::boost::numeric::interval_lib::user::is_neg(yu))
42      return I(rnd.div_down(xu, yu), rnd.div_up(xl, yu), true);
43    else
44      return I(rnd.div_down(xl, yl), rnd.div_up(xu, yl), true);
45  else
46    if (::boost::numeric::interval_lib::user::is_neg(yu))
47      return I(rnd.div_down(xu, yu), rnd.div_up(xl, yl), true);
48    else
49      return I(rnd.div_down(xl, yu), rnd.div_up(xu, yl), true);
50}
51
52template<class T, class Policies> inline
53interval<T, Policies> div_non_zero(const T& x, const interval<T, Policies>& y)
54{
55  // assert(!in_zero(y));
56  typename Policies::rounding rnd;
57  typedef interval<T, Policies> I;
58  const T& yl = y.lower();
59  const T& yu = y.upper();
60  if (::boost::numeric::interval_lib::user::is_neg(x))
61    return I(rnd.div_down(x, yl), rnd.div_up(x, yu), true);
62  else
63    return I(rnd.div_down(x, yu), rnd.div_up(x, yl), true);
64}
65
66template<class T, class Policies> inline
67interval<T, Policies> div_positive(const interval<T, Policies>& x, const T& yu)
68{
69  // assert(::boost::numeric::interval_lib::user::is_pos(yu));
70  if (::boost::numeric::interval_lib::user::is_zero(x.lower()) &&
71      ::boost::numeric::interval_lib::user::is_zero(x.upper()))
72    return x;
73  typename Policies::rounding rnd;
74  typedef interval<T, Policies> I;
75  const T& xl = x.lower();
76  const T& xu = x.upper();
77  typedef typename Policies::checking checking;
78  if (::boost::numeric::interval_lib::user::is_neg(xu))
79    return I(checking::neg_inf(), rnd.div_up(xu, yu), true);
80  else if (::boost::numeric::interval_lib::user::is_neg(xl))
81    return I(checking::neg_inf(), checking::pos_inf(), true);
82  else
83    return I(rnd.div_down(xl, yu), checking::pos_inf(), true);
84}
85
86template<class T, class Policies> inline
87interval<T, Policies> div_positive(const T& x, const T& yu)
88{
89  // assert(::boost::numeric::interval_lib::user::is_pos(yu));
90  typedef interval<T, Policies> I;
91  if (::boost::numeric::interval_lib::user::is_zero(x))
92    return I(static_cast<T>(0), static_cast<T>(0), true);
93  typename Policies::rounding rnd;
94  typedef typename Policies::checking checking;
95  if (::boost::numeric::interval_lib::user::is_neg(x))
96    return I(checking::neg_inf(), rnd.div_up(x, yu), true);
97  else
98    return I(rnd.div_down(x, yu), checking::pos_inf(), true);
99}
100
101template<class T, class Policies> inline
102interval<T, Policies> div_negative(const interval<T, Policies>& x, const T& yl)
103{
104  // assert(::boost::numeric::interval_lib::user::is_neg(yl));
105  if (::boost::numeric::interval_lib::user::is_zero(x.lower()) &&
106      ::boost::numeric::interval_lib::user::is_zero(x.upper()))
107    return x;
108  typename Policies::rounding rnd;
109  typedef interval<T, Policies> I;
110  const T& xl = x.lower();
111  const T& xu = x.upper();
112  typedef typename Policies::checking checking;
113  if (::boost::numeric::interval_lib::user::is_neg(xu))
114    return I(rnd.div_down(xu, yl), checking::pos_inf(), true);
115  else if (::boost::numeric::interval_lib::user::is_neg(xl))
116    return I(checking::neg_inf(), checking::pos_inf(), true);
117  else
118    return I(checking::neg_inf(), rnd.div_up(xl, yl), true);
119}
120
121template<class T, class Policies> inline
122interval<T, Policies> div_negative(const T& x, const T& yl)
123{
124  // assert(::boost::numeric::interval_lib::user::is_neg(yl));
125  typedef interval<T, Policies> I;
126  if (::boost::numeric::interval_lib::user::is_zero(x))
127    return I(static_cast<T>(0), static_cast<T>(0), true);
128  typename Policies::rounding rnd;
129  typedef typename Policies::checking checking;
130  if (::boost::numeric::interval_lib::user::is_neg(x))
131    return I(rnd.div_down(x, yl), checking::pos_inf(), true);
132  else
133    return I(checking::neg_inf(), rnd.div_up(x, yl), true);
134}
135
136template<class T, class Policies> inline
137interval<T, Policies> div_zero(const interval<T, Policies>& x)
138{
139  if (::boost::numeric::interval_lib::user::is_zero(x.lower()) &&
140      ::boost::numeric::interval_lib::user::is_zero(x.upper()))
141    return x;
142  else return interval<T, Policies>::whole();
143}
144
145template<class T, class Policies> inline
146interval<T, Policies> div_zero(const T& x)
147{
148  if (::boost::numeric::interval_lib::user::is_zero(x))
149    return interval<T, Policies>(static_cast<T>(0), static_cast<T>(0), true);
150  else return interval<T, Policies>::whole();
151}
152
153template<class T, class Policies> inline
154interval<T, Policies> div_zero_part1(const interval<T, Policies>& x,
155                                     const interval<T, Policies>& y, bool& b)
156{
157  // assert(::boost::numeric::interval_lib::user::is_neg(y.lower()) && ::boost::numeric::interval_lib::user::is_pos(y.upper()));
158  if (::boost::numeric::interval_lib::user::is_zero(x.lower()) && ::boost::numeric::interval_lib::user::is_zero(x.upper()))
159    { b = false; return x; }
160  typename Policies::rounding rnd;
161  typedef interval<T, Policies> I;
162  const T& xl = x.lower();
163  const T& xu = x.upper();
164  const T& yl = y.lower();
165  const T& yu = y.upper();
166  typedef typename Policies::checking checking;
167  if (::boost::numeric::interval_lib::user::is_neg(xu))
168    { b = true;  return I(checking::neg_inf(), rnd.div_up(xu, yu), true); }
169  else if (::boost::numeric::interval_lib::user::is_neg(xl))
170    { b = false; return I(checking::neg_inf(), checking::pos_inf(), true); }
171  else
172    { b = true;  return I(checking::neg_inf(), rnd.div_up(xl, yl), true); }
173}
174
175template<class T, class Policies> inline
176interval<T, Policies> div_zero_part2(const interval<T, Policies>& x,
177                                     const interval<T, Policies>& y)
178{
179  // assert(::boost::numeric::interval_lib::user::is_neg(y.lower()) && ::boost::numeric::interval_lib::user::is_pos(y.upper()) && (div_zero_part1(x, y, b), b));
180  typename Policies::rounding rnd;
181  typedef interval<T, Policies> I;
182  typedef typename Policies::checking checking;
183  if (::boost::numeric::interval_lib::user::is_neg(x.upper()))
184    return I(rnd.div_down(x.upper(), y.lower()), checking::pos_inf(), true);
185  else
186    return I(rnd.div_down(x.lower(), y.upper()), checking::pos_inf(), true);
187}
188
189} // namespace detail
190} // namespace interval_lib
191} // namespace numeric
192} // namespace boost
193
194#endif // BOOST_NUMERIC_INTERVAL_DETAIL_DIVISION_HPP
Note: See TracBrowser for help on using the repository browser.