summaryrefslogtreecommitdiffstats
path: root/src/boost/libs/math/test/test_igamma_inv.hpp
blob: 7330e918a7ed4d5ec80f2cfe20f2d09d5699cba6 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
// Copyright John Maddock 2006.
// Copyright Paul A. Bristow 2007, 2009
//  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)

#include <boost/math/concepts/real_concept.hpp>
#include <boost/math/special_functions/math_fwd.hpp>
#define BOOST_TEST_MAIN
#include <boost/test/unit_test.hpp>
#include <boost/test/results_collector.hpp>
#include <boost/test/unit_test.hpp>
#include <boost/test/tools/floating_point_comparison.hpp>
#include <boost/math/tools/stats.hpp>
#include <boost/math/tools/test.hpp>
#include <boost/math/constants/constants.hpp>
#include <boost/type_traits/is_floating_point.hpp>
#include <boost/array.hpp>
#include "functor.hpp"

#include "handle_test_result.hpp"
#include "table_type.hpp"

#ifndef SC_
#define SC_(x) static_cast<typename table_type<T>::type>(BOOST_JOIN(x, L))
#endif

#define BOOST_CHECK_CLOSE_EX(a, b, prec, i) \
   {\
      unsigned int failures = boost::unit_test::results_collector.results( boost::unit_test::framework::current_test_case().p_id ).p_assertions_failed;\
      BOOST_CHECK_CLOSE(a, b, prec); \
      if(failures != boost::unit_test::results_collector.results( boost::unit_test::framework::current_test_case().p_id ).p_assertions_failed)\
      {\
         std::cerr << "Failure was at row " << i << std::endl;\
         std::cerr << std::setprecision(35); \
         std::cerr << "{ " << data[i][0] << " , " << data[i][1] << " , " << data[i][2];\
         std::cerr << " , " << data[i][3] << " , " << data[i][4] << " , " << data[i][5] << " } " << std::endl;\
      }\
   }

template <class Real, class T>
void do_test_gamma_2(const T& data, const char* type_name, const char* test_name)
{
   //
   // test gamma_p_inv(T, T) against data:
   //
   using namespace std;
   typedef Real                   value_type;

   std::cout << test_name << " with type " << type_name << std::endl;

   //
   // These sanity checks test for a round trip accuracy of one half
   // of the bits in T, unless T is type float, in which case we check
   // for just one decimal digit.  The problem here is the sensitivity
   // of the functions, not their accuracy.  This test data was generated
   // for the forward functions, which means that when it is used as
   // the input to the inverses then it is necessarily inexact.  This rounding
   // of the input is what makes the data unsuitable for use as an accuracy check,
   // and also demonstrates that you can't in general round-trip these functions.
   // It is however a useful sanity check.
   //
   value_type precision = static_cast<value_type>(ldexp(1.0, 1-boost::math::policies::digits<value_type, boost::math::policies::policy<> >()/2)) * 100;
   if(boost::math::policies::digits<value_type, boost::math::policies::policy<> >() < 50)
      precision = 1;   // 1% or two decimal digits, all we can hope for when the input is truncated to float

   for(unsigned i = 0; i < data.size(); ++i)
   {
      //
      // These inverse tests are thrown off if the output of the
      // incomplete gamma is too close to 1: basically there is insuffient
      // information left in the value we're using as input to the inverse
      // to be able to get back to the original value.
      //
      if(Real(data[i][5]) == 0)
         BOOST_CHECK_EQUAL(boost::math::gamma_p_inv(Real(data[i][0]), Real(data[i][5])), value_type(0));
      else if((1 - Real(data[i][5]) > 0.001) 
         && (fabs(Real(data[i][5])) > 2 * boost::math::tools::min_value<value_type>()) 
         && (fabs(Real(data[i][5])) > 2 * boost::math::tools::min_value<double>()))
      {
         value_type inv = boost::math::gamma_p_inv(Real(data[i][0]), Real(data[i][5]));
         BOOST_CHECK_CLOSE_EX(Real(data[i][1]), inv, precision, i);
      }
      else if(1 == Real(data[i][5]))
         BOOST_CHECK_EQUAL(boost::math::gamma_p_inv(Real(data[i][0]), Real(data[i][5])), std::numeric_limits<value_type>::has_infinity ? std::numeric_limits<value_type>::infinity() : boost::math::tools::max_value<value_type>());
      else
      {
         // not enough bits in our input to get back to x, but we should be in
         // the same ball park:
         value_type inv = boost::math::gamma_p_inv(Real(data[i][0]), Real(data[i][5]));
         BOOST_CHECK_CLOSE_EX(Real(data[i][1]), inv, 100000, i);
      }

      if(Real(data[i][3]) == 0)
         BOOST_CHECK_EQUAL(boost::math::gamma_q_inv(Real(data[i][0]), Real(data[i][3])), std::numeric_limits<value_type>::has_infinity ? std::numeric_limits<value_type>::infinity() : boost::math::tools::max_value<value_type>());
      else if((1 - Real(data[i][3]) > 0.001) && (fabs(Real(data[i][3])) > 2 * boost::math::tools::min_value<value_type>()))
      {
         value_type inv = boost::math::gamma_q_inv(Real(data[i][0]), Real(data[i][3]));
         BOOST_CHECK_CLOSE_EX(Real(data[i][1]), inv, precision, i);
      }
      else if(1 == Real(data[i][3]))
         BOOST_CHECK_EQUAL(boost::math::gamma_q_inv(Real(data[i][0]), Real(data[i][3])), value_type(0));
      else if(fabs(Real(data[i][3])) > 2 * boost::math::tools::min_value<value_type>())
      {
         // not enough bits in our input to get back to x, but we should be in
         // the same ball park:
         value_type inv = boost::math::gamma_q_inv(Real(data[i][0]), Real(data[i][3]));
         BOOST_CHECK_CLOSE_EX(Real(data[i][1]), inv, 100, i);
      }
   }
   std::cout << std::endl;
}

template <class Real, class T>
void do_test_gamma_inv(const T& data, const char* type_name, const char* test_name)
{
#if !(defined(ERROR_REPORTING_MODE) && !defined(GAMMAP_INV_FUNCTION_TO_TEST))
   typedef Real                   value_type;

   typedef value_type (*pg)(value_type, value_type);
#ifdef GAMMAP_INV_FUNCTION_TO_TEST
   pg funcp = GAMMAP_INV_FUNCTION_TO_TEST;
#elif defined(BOOST_MATH_NO_DEDUCED_FUNCTION_POINTERS)
   pg funcp = boost::math::gamma_p_inv<value_type, value_type>;
#else
   pg funcp = boost::math::gamma_p_inv;
#endif

   boost::math::tools::test_result<value_type> result;

   std::cout << "Testing " << test_name << " with type " << type_name
      << "\n~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~\n";

   //
   // test gamma_p_inv(T, T) against data:
   //
   result = boost::math::tools::test_hetero<Real>(
      data,
      bind_func<Real>(funcp, 0, 1),
      extract_result<Real>(2));
   handle_test_result(result, data[result.worst()], result.worst(), type_name, "gamma_p_inv", test_name);
   //
   // test gamma_q_inv(T, T) against data:
   //
#ifdef GAMMAQ_INV_FUNCTION_TO_TEST
   funcp = GAMMAQ_INV_FUNCTION_TO_TEST;
#elif defined(BOOST_MATH_NO_DEDUCED_FUNCTION_POINTERS)
   funcp = boost::math::gamma_q_inv<value_type, value_type>;
#else
   funcp = boost::math::gamma_q_inv;
#endif
   result = boost::math::tools::test_hetero<Real>(
      data,
      bind_func<Real>(funcp, 0, 1),
      extract_result<Real>(3));
   handle_test_result(result, data[result.worst()], result.worst(), type_name, "gamma_q_inv", test_name);
#endif
}

template <class T>
void test_gamma(T, const char* name)
{
#if !defined(TEST_UDT) && !defined(ERROR_REPORTING_MODE)
   //
   // The actual test data is rather verbose, so it's in a separate file
   //
   // First the data for the incomplete gamma function, each
   // row has the following 6 entries:
   // Parameter a, parameter z,
   // Expected tgamma(a, z), Expected gamma_q(a, z)
   // Expected tgamma_lower(a, z), Expected gamma_p(a, z)
   //
#  include "igamma_med_data.ipp"

   do_test_gamma_2<T>(igamma_med_data, name, "Running round trip sanity checks on incomplete gamma medium sized values");

#  include "igamma_small_data.ipp"

   do_test_gamma_2<T>(igamma_small_data, name, "Running round trip sanity checks on incomplete gamma small values");

#  include "igamma_big_data.ipp"

   do_test_gamma_2<T>(igamma_big_data, name, "Running round trip sanity checks on incomplete gamma large values");

#endif

#  include "gamma_inv_data.ipp"

   do_test_gamma_inv<T>(gamma_inv_data, name, "incomplete gamma inverse(a, z) medium values");

#  include "gamma_inv_big_data.ipp"

   do_test_gamma_inv<T>(gamma_inv_big_data, name, "incomplete gamma inverse(a, z) large values");

#  include "gamma_inv_small_data.ipp"

   do_test_gamma_inv<T>(gamma_inv_small_data, name, "incomplete gamma inverse(a, z) small values");
}

template <class T>
void test_spots(T, const char* type_name)
{
   std::cout << "Running spot checks for type " << type_name << std::endl;
   //
   // basic sanity checks, tolerance is 150 epsilon expressed as a percentage:
   //
   T tolerance = boost::math::tools::epsilon<T>() * 15000;
   if(tolerance < 1e-25f)
      tolerance = 1e-25f;  // limit of test data?
   BOOST_CHECK_CLOSE(::boost::math::gamma_q_inv(static_cast<T>(1)/100, static_cast<T>(1.0/128)), static_cast<T>(0.35767144525455121503672919307647515332256996883787L), tolerance);
   BOOST_CHECK_CLOSE(::boost::math::gamma_q_inv(static_cast<T>(1)/100, static_cast<T>(0.5)), static_cast<T>(4.4655350189103486773248562646452806745879516124613e-31L), tolerance*10);
   //
   // We can't test in this region against Mathworld's data as the results produced
   // by functions.wolfram.com appear to be in error, and do *not* round trip with
   // their own version of gamma_q.  Using our output from the inverse as input to 
   // their version of gamma_q *does* round trip however.  It should be pointed out
   // that the functions in this area are very sensitive with nearly infinite
   // first derivatives, it's also questionable how useful these functions are
   // in this part of the domain.
   //
   //BOOST_CHECK_CLOSE(::boost::math::gamma_q_inv(static_cast<T>(1e-2), static_cast<T>(1.0-1.0/128)), static_cast<T>(3.8106736649978161389878528903698068142257930575497e-181L), tolerance);
   //
   BOOST_CHECK_CLOSE(::boost::math::gamma_q_inv(static_cast<T>(0.5), static_cast<T>(1.0/128)), static_cast<T>(3.5379794687984498627918583429482809311448951189097L), tolerance);
   BOOST_CHECK_CLOSE(::boost::math::gamma_q_inv(static_cast<T>(0.5), static_cast<T>(1.0/2)), static_cast<T>(0.22746821155978637597125832348982469815821055329511L), tolerance);
   BOOST_CHECK_CLOSE(::boost::math::gamma_q_inv(static_cast<T>(0.5), static_cast<T>(1.0-1.0/128)), static_cast<T>(0.000047938431649305382237483273209405461203600840052182L), tolerance);
   BOOST_CHECK_CLOSE(::boost::math::gamma_q_inv(static_cast<T>(10), static_cast<T>(1.0/128)), static_cast<T>(19.221865946801723949866005318845155649972164294057L), tolerance);
   BOOST_CHECK_CLOSE(::boost::math::gamma_q_inv(static_cast<T>(10), static_cast<T>(1.0/2)), static_cast<T>(9.6687146147141311517500637401166726067778162022664L), tolerance);
   BOOST_CHECK_CLOSE(::boost::math::gamma_q_inv(static_cast<T>(10), static_cast<T>(1.0-1.0/128)), static_cast<T>(3.9754602513640844712089002210120603689809432130520L), tolerance);
   BOOST_CHECK_CLOSE(::boost::math::gamma_q_inv(static_cast<T>(10000), static_cast<T>(1.0/128)), static_cast<T>(10243.369973939134157953734588122880006091919872879L), tolerance);
   BOOST_CHECK_CLOSE(::boost::math::gamma_q_inv(static_cast<T>(10000), static_cast<T>(1.0/2)), static_cast<T>(9999.6666686420474237369661574633153551436435884101L), tolerance);
   BOOST_CHECK_CLOSE(::boost::math::gamma_q_inv(static_cast<T>(10000), static_cast<T>(1.0-1.0/128)), static_cast<T>(9759.8597223369324083191194574874497413261589080204L), tolerance);
}