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Fix AlmostEqual. Add more unit tests.

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vng 2011-01-26 21:25:12 +02:00 • committed by Alex Zolotarev
parent 58b80c1da5
commit 5dec38415e
2 changed files with 23 additions and 6 deletions
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12
base/base_tests/math_test.cpp
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@ -45,9 +45,21 @@ UNIT_TEST(AlmostEqual_Smoke)
TEST_ALMOST_EQUAL(+0.0, -0.0, ());
double const eps = numeric_limits<double>::epsilon();
double const dmax = numeric_limits<double>::max();
TEST_ALMOST_EQUAL(1.0 + eps, 1.0, ());
TEST_ALMOST_EQUAL(1.0 - eps, 1.0, ());
TEST_ALMOST_EQUAL(1.0 - eps, 1.0 + eps, ());
TEST_ALMOST_EQUAL(dmax, dmax, ());
TEST_ALMOST_EQUAL(-dmax, -dmax, ());
TEST_ALMOST_EQUAL(dmax/2.0, dmax/2.0, ());
TEST_ALMOST_EQUAL(1.0/dmax, 1.0/dmax, ());
TEST_ALMOST_EQUAL(-1.0/dmax, -1.0/dmax, ());
TEST(!my::AlmostEqual(1.0, -1.0), ());
TEST(!my::AlmostEqual(2.0, -2.0), ());
TEST(!my::AlmostEqual(dmax, -dmax), ());
}
namespace

17
base/math.hpp
View file

@ -1,9 +1,11 @@
#pragma once
#include "../base/assert.hpp"
#include "../base/base.hpp"
#include "../base/assert.hpp"
#include "../std/cmath.hpp"
#include "../std/limits.hpp"
#include "../std/type_traits.hpp"
#include <boost/integer.hpp>
namespace my
@ -20,25 +22,28 @@ template <typename FloatT> bool AlmostEqual(FloatT x, FloatT y, unsigned int max
STATIC_ASSERT(numeric_limits<FloatT>::is_iec559);
STATIC_ASSERT(!numeric_limits<FloatT>::is_exact);
STATIC_ASSERT(!numeric_limits<FloatT>::is_integer);
// Make sure maxUlps is non-negative and small enough that the
// default NAN won't compare as equal to anything.
ASSERT_LESS(maxULPs, 4 * 1024 * 1024, ());
typedef typename boost::int_t<8 * sizeof(FloatT)>::exact IntType;
int const bits = 8 * sizeof(FloatT);
typedef typename boost::int_t<bits>::exact IntType;
typedef typename boost::uint_t<bits>::exact UIntType;
IntType xInt = *reinterpret_cast<IntType const *>(&x);
IntType yInt = *reinterpret_cast<IntType const *>(&y);
// Make xInt and yInt lexicographically ordered as a twos-complement int
IntType const highestBit = IntType(1) << (sizeof(FloatT) * 8 - 1);
IntType const highestBit = IntType(1) << (bits - 1);
if (xInt < 0)
xInt = highestBit - xInt;
if (yInt < 0)
yInt = highestBit - yInt;
IntType const diff = Abs(xInt - yInt);
UIntType const diff = Abs(xInt - yInt);
return diff <= static_cast<IntType>(maxULPs);
return (diff <= maxULPs);
}
template <typename TFloat> inline TFloat DegToRad(TFloat deg)
@ -72,7 +77,7 @@ template <typename T, typename TMinMax> inline T clamp(T x, TMinMax xmin, TMinMa
template <typename T> inline T Abs(T x)
{
return x >= 0 ? x : -x;
return (x < 0 ? -x : x);
}
template <typename T> inline bool between_s(T a, T b, T x)