libcruft-util/test/maths.cpp
Danny Robson b18feb8bc4 maths: use bit patterns for tests float values
this makes some of the tests more robust in the face of (potentially
stanard breaking) optimisations.
2017-07-25 17:08:52 +10:00

193 lines
6.9 KiB
C++

#include "maths.hpp"
#include "debug.hpp"
#include "tap.hpp"
#include <cstdlib>
#include <cmath>
#include <limits>
using std::sqrt;
using std::numeric_limits;
void
test_comparisons (util::TAP::logger &tap)
{
// Check pos/neg zeroes
tap.expect (util::almost_equal ( 0.f, 0.f), "equal float zeros +ve/+ve");
tap.expect (util::almost_equal ( 0.f, -0.f), "equal float zeros +ve/-ve");
tap.expect (util::almost_equal (-0.f, 0.f), "equal float zeros -ve/+ve");
tap.expect (util::almost_equal (-0.f, -0.f), "equal float zeros -ve/-ve");
tap.expect (util::almost_equal ( 0., 0.), "equal double zeroes +ve/+ve");
tap.expect (util::almost_equal ( 0., -0.), "equal double zeroes +ve/+ve");
tap.expect (util::almost_equal (-0., 0.), "equal double zeroes +ve/+ve");
tap.expect (util::almost_equal (-0., -0.), "equal double zeroes +ve/+ve");
// Check zero comparison with values near the expected cutoff
tap.expect (util::almost_zero (1e-45f), "almost_zero with low value");
tap.expect (!util::almost_zero (1e-40f), "not almost_zero with low value");
tap.expect (!util::exactly_zero (1e-45f), "not exactly_zero with low value");
// Compare values a little away from zero
tap.expect (!util::almost_equal (-2.0, 0.0), "not equal floats");
tap.expect (!util::almost_equal (-2.f, 0.f), "not equal doubles");
// Compare values at the maximum extreme
tap.expect (!util::almost_equal (-std::numeric_limits<float>::max (), 0.f), "not equal -max/0 float");
tap.expect (!util::almost_equal (-std::numeric_limits<float>::max (),
std::numeric_limits<float>::max ()),
"not equal -max/max");
// Compare infinity values
tap.expect ( util::almost_equal (numeric_limits<double>::infinity (),
numeric_limits<double>::infinity ()),
"almost_equal +infinity");
tap.expect (!util::almost_equal (numeric_limits<double>::infinity (), 0.0),
"not almost_equal +inf/0");
// Compare NaNs
tap.expect (!util::almost_equal (0., numeric_limits<double>::quiet_NaN ()), "not almost_equal double 0/NaN");
tap.expect (!util::almost_equal (numeric_limits<double>::quiet_NaN (), 0.), "not almost_equal double NaN/0");
tap.expect (!util::almost_equal (numeric_limits<double>::quiet_NaN (),
numeric_limits<double>::quiet_NaN ()),
"not almost_equal NaN/NaN");
// Compare reasonably close values that are wrong
tap.expect (!util::almost_equal (1.0000f, 1.0001f), ".0001f difference inequality");
tap.expect ( util::almost_equal (1.0000f, 1.00001f), ".00001f difference inequality");
}
void
test_normalisations (util::TAP::logger &tap)
{
// u8 to float
{
auto a = util::renormalise<uint8_t,float> (255);
tap.expect_eq (a, 1.f, "normalise uint8 max");
auto b = util::renormalise<uint8_t,float> (0);
tap.expect_eq (b, 0.f, "normalise uint8 min");
}
// float to u8
{
bool success = true;
static const struct {
float a;
uint8_t b;
} TESTS[] = {
{ 1.f, 255 },
{ 0.5f, 127 },
{ 2.f, 255 },
{ -1.f, 0 }
};
for (auto i: TESTS) {
auto v = util::renormalise<decltype(i.a),decltype(i.b)> (i.a);
success = success && util::almost_equal (unsigned{v}, unsigned{i.b});
}
tap.expect (success, "float-u8 normalisation");
}
// float to uint32
// exercises an integer type that has more precision than float
{
bool success = true;
static const struct {
float a;
uint32_t b;
} TESTS[] {
{ 0.f, 0x00000000 }, // lo range
{ 1.f, 0xffffffff }, // hi range
{ 0.5f, 0x7fffff7f }, // 31 bits
{ 0.001953125f, 0x007fff00 }, // 23 bits
};
for (auto t: TESTS) {
auto v = util::renormalise<float,uint32_t> (t.a);
success = success && util::almost_equal (t.b, v);
}
tap.expect (success, "float-u32 normalisation");
}
tap.expect_eq (util::renormalise<uint8_t,uint32_t> (0xff), 0xffffffffu, "normalise hi u8-to-u32");
tap.expect_eq (util::renormalise<uint8_t,uint32_t> (0x00), 0x00000000u, "normalise lo u8-to-u32");
tap.expect_eq (util::renormalise<uint32_t,uint8_t> (0xffffffff), 0xffu, "normalise hi u32-to-u8");
// sint32 to uint32
{
static const struct {
int32_t sint;
uint32_t uint;
const char *msg;
} TESTS[] = {
{ std::numeric_limits<int32_t>::min (), std::numeric_limits<uint32_t>::min (), "min" },
{ std::numeric_limits<int32_t>::max (), std::numeric_limits<uint32_t>::max (), "max" },
{ 0, std::numeric_limits<uint32_t>::max () / 2u + 1, "mid" },
};
for (const auto &t: TESTS) {
tap.expect_eq (util::renormalise<int32_t,uint32_t> (t.sint), t.uint, "%s s32-to-u32", t.msg);
tap.expect_eq (util::renormalise<uint32_t,int32_t> (t.uint), t.sint, "%s u32-to-s32", t.msg);
}
}
}
int
main (void)
{
util::TAP::logger tap;
// Max out the precision in case we trigger debug output
std::cerr.precision (std::numeric_limits<double>::digits10);
std::cout.precision (std::numeric_limits<double>::digits10);
test_comparisons (tap);
test_normalisations (tap);
tap.expect_eq (util::min (-2, 0, 2), -2, "variadic min");
tap.expect_eq (util::max (-2, 0, 2), 2, "variadic max");
tap.expect_eq (util::pow2 (4u), 16u, "pow2");
static const float POS_ZERO = 1.f / numeric_limits<float>::infinity ();
union {
uint32_t neg_zero_bits = 0x80000000;
float NEG_ZERO;
};
tap.expect_eq (util::sign (-1), -1, "sign(-1)");
tap.expect_eq (util::sign ( 1), 1, "sign( 1)");
tap.expect_eq (util::sign (POS_ZERO), 1.f, "sign (POS_ZERO)");
tap.expect_eq (util::sign (NEG_ZERO), -1.f, "sign (NEG_ZERO)");
tap.expect_eq (util::sign ( numeric_limits<double>::infinity ()), 1., "sign +inf");
tap.expect_eq (util::sign (-numeric_limits<double>::infinity ()), -1., "sign -inf");
tap.expect_eq (util::to_degrees (util::PI< float>), 180.f, "to_degrees float");
tap.expect_eq (util::to_degrees (util::PI<double>), 180.0, "to_degrees double");
tap.expect_eq (util::to_radians (180.f), util::PI<float>, "to_radians float");
tap.expect_eq (util::to_radians (180.0), util::PI<double>, "to_radians double");
tap.expect_eq (util::log2 (8u), 3u, "log2 +ve");
tap.expect_eq (util::log2 (1u), 0u, "log2 zero");
//tap.expect_eq (log2 (9u), 3, "log2up 9");
tap.expect_eq (util::log2up (9u), 4u, "log2up 9");
tap.expect_eq (util::log2up (8u), 3u, "log2up 9");
tap.expect_eq (util::log2up (1u), 0u, "log2up 9");
return tap.status ();
}