libs/math/test/hypot_test.cpp

   1 //  (C) Copyright John Maddock 2005.
   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 #include <pch_light.hpp>
   7
   8 #define BOOST_MATH_OVERFLOW_ERROR_POLICY ignore_error
   9 #define BOOST_TEST_MAIN
  10 #include <boost/test/unit_test.hpp>
  11 #include <boost/test/floating_point_comparison.hpp>
  12 #include <boost/math/special_functions/math_fwd.hpp>
  13
  14 #include <cmath>
  15
  16 #ifdef BOOST_NO_STDC_NAMESPACE
  17 namespace std{ using ::sqrt; }
  18 #endif
  19
  20 //
  21 // test_boundaries:
  22 // This is an accuracy test, sets the two arguments to hypot to just
  23 // above or just below various boundary conditions, and checks the accuracy
  24 // of the result.  The values computed at double precision will use a
  25 // different computation method to those computed at float precision:
  26 // as long as these compute the same values then everything's OK.
  27 //
  28 // Tolerance is 2*epsilon, expressed here as a persentage:
  29 //
  30 static const float tolerance = 200 * (std::numeric_limits<float>::epsilon)();
  31 const float boundaries[] = {
  32    0,
  33    1,
  34    2,
  35    (std::numeric_limits<float>::max)()/2,
  36    (std::numeric_limits<float>::min)(),
  37    std::numeric_limits<float>::epsilon(),
  38    std::sqrt((std::numeric_limits<float>::max)()) / 2,
  39    std::sqrt((std::numeric_limits<float>::min)()),
  40    std::sqrt((std::numeric_limits<float>::max)()) / 4,
  41    std::sqrt((std::numeric_limits<float>::min)()) * 2,
  42 };
  43
  44 void do_test_boundaries(float x, float y)
  45 {
  46    float expected = static_cast<float>((boost::math::hypot)(
  47 #ifndef BOOST_MATH_NO_LONG_DOUBLE_MATH_FUNCTIONS
  48       static_cast<long double>(x),
  49       static_cast<long double>(y)));
  50 #else
  51       static_cast<double>(x),
  52       static_cast<double>(y)));
  53 #endif
  54    float found = (boost::math::hypot)(x, y);
  55    BOOST_CHECK_CLOSE(expected, found, tolerance);
  56 }
  57
  58 void test_boundaries(float x, float y)
  59 {
  60    do_test_boundaries(x, y);
  61    do_test_boundaries(-x, y);
  62    do_test_boundaries(-x, -y);
  63    do_test_boundaries(x, -y);
  64 }
  65
  66 void test_boundaries(float x)
  67 {
  68    for(unsigned i = 0; i < sizeof(boundaries)/sizeof(float); ++i)
  69    {
  70       test_boundaries(x, boundaries[i]);
  71       test_boundaries(x, boundaries[i] + std::numeric_limits<float>::epsilon()*boundaries[i]);
  72       test_boundaries(x, boundaries[i] - std::numeric_limits<float>::epsilon()*boundaries[i]);
  73    }
  74 }
  75
  76 void test_boundaries()
  77 {
  78    for(unsigned i = 0; i < sizeof(boundaries)/sizeof(float); ++i)
  79    {
  80       test_boundaries(boundaries[i]);
  81       test_boundaries(boundaries[i] + std::numeric_limits<float>::epsilon()*boundaries[i]);
  82       test_boundaries(boundaries[i] - std::numeric_limits<float>::epsilon()*boundaries[i]);
  83    }
  84 }
  85
  86 void test_spots()
  87 {
  88    static const float zero = 0;
  89    for(unsigned i = 0; i < sizeof(boundaries)/sizeof(float); ++i)
  90    {
  91       BOOST_CHECK_EQUAL(boost::math::hypot(boundaries[i], zero), std::fabs(boundaries[i]));
  92       BOOST_CHECK_EQUAL(boost::math::hypot(-boundaries[i], zero), std::fabs(-boundaries[i]));
  93       BOOST_CHECK_EQUAL(boost::math::hypot(boundaries[i], -zero), std::fabs(boundaries[i]));
  94       BOOST_CHECK_EQUAL(boost::math::hypot(-boundaries[i], -zero), std::fabs(-boundaries[i]));
  95       for(unsigned j = 0; j < sizeof(boundaries)/sizeof(float); ++j)
  96       {
  97          BOOST_CHECK_EQUAL(boost::math::hypot(boundaries[i], boundaries[j]), boost::math::hypot(boundaries[j], boundaries[i]));
  98          BOOST_CHECK_EQUAL(boost::math::hypot(boundaries[i], boundaries[j]), boost::math::hypot(boundaries[i], -boundaries[j]));
  99          BOOST_CHECK_EQUAL(boost::math::hypot(-boundaries[i], -boundaries[j]), boost::math::hypot(-boundaries[j], -boundaries[i]));
 100          BOOST_CHECK_EQUAL(boost::math::hypot(-boundaries[i], -boundaries[j]), boost::math::hypot(-boundaries[i], boundaries[j]));
 101       }
 102    }
 103    if((std::numeric_limits<float>::has_infinity) && (std::numeric_limits<float>::has_quiet_NaN))
 104    {
 105       static const float nan = std::numeric_limits<float>::quiet_NaN();
 106       static const float inf = std::numeric_limits<float>::infinity();
 107       BOOST_CHECK_EQUAL(boost::math::hypot(inf, nan), inf);
 108       BOOST_CHECK_EQUAL(boost::math::hypot(-inf, nan), inf);
 109       BOOST_CHECK_EQUAL(boost::math::hypot(nan, inf), inf);
 110       BOOST_CHECK_EQUAL(boost::math::hypot(nan, -inf), inf);
 111       for(unsigned j = 0; j < sizeof(boundaries)/sizeof(float); ++j)
 112       {
 113          BOOST_CHECK_EQUAL(boost::math::hypot(boundaries[j], inf), inf);
 114          BOOST_CHECK_EQUAL(boost::math::hypot(-boundaries[j], inf), inf);
 115          BOOST_CHECK_EQUAL(boost::math::hypot(inf, boundaries[j]), inf);
 116          BOOST_CHECK_EQUAL(boost::math::hypot(inf, -boundaries[j]), inf);
 117          BOOST_CHECK_EQUAL(boost::math::hypot(boundaries[j], -inf), inf);
 118          BOOST_CHECK_EQUAL(boost::math::hypot(-boundaries[j], -inf), inf);
 119          BOOST_CHECK_EQUAL(boost::math::hypot(-inf, boundaries[j]), inf);
 120          BOOST_CHECK_EQUAL(boost::math::hypot(-inf, -boundaries[j]), inf);
 121       }
 122    }
 123 }
 124
 125 BOOST_AUTO_TEST_CASE( test_main )
 126 {
 127    BOOST_MATH_CONTROL_FP;
 128    test_boundaries();
 129    test_spots();
 130 }