libcruft-util/test/maths.cpp
Danny Robson 08b6cbacea float: lower ULPs threshold for almost_equal
we weren't detecting differences with 4 decimal point differences
2015-08-20 15:34:20 +10:00

146 lines
5.0 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 (almost_equal ( 0.f, 0.f), "equal float zeros +ve/+ve");
tap.expect (almost_equal ( 0.f, -0.f), "equal float zeros +ve/-ve");
tap.expect (almost_equal (-0.f, 0.f), "equal float zeros -ve/+ve");
tap.expect (almost_equal (-0.f, -0.f), "equal float zeros -ve/-ve");
tap.expect (almost_equal ( 0., 0.), "equal double zeroes +ve/+ve");
tap.expect (almost_equal ( 0., -0.), "equal double zeroes +ve/+ve");
tap.expect (almost_equal (-0., 0.), "equal double zeroes +ve/+ve");
tap.expect (almost_equal (-0., -0.), "equal double zeroes +ve/+ve");
// Check zero comparison with values near the expected cutoff
tap.expect (almost_zero (1e-45f), "almost_zero with low value");
tap.expect (!almost_zero (1e-40f), "not almost_zero with low value");
tap.expect (!exactly_zero (1e-45f), "not exactly_zero with low value");
// Compare values a little away from zero
tap.expect (!almost_equal (-2.0, 0.0), "not equal floats");
tap.expect (!almost_equal (-2.f, 0.f), "not equal doubles");
// Compare values at the maximum extreme
tap.expect (!almost_equal (-std::numeric_limits<float>::max (), 0.f), "not equal -max/0 float");
tap.expect (!almost_equal (-std::numeric_limits<float>::max (),
std::numeric_limits<float>::max ()),
"not equal -max/max");
// Compare infinity values
tap.expect ( almost_equal (numeric_limits<double>::infinity (),
numeric_limits<double>::infinity ()),
"almost_equal +infinity");
tap.expect (!almost_equal (numeric_limits<double>::infinity (), 0.0),
"not almost_equal +inf/0");
// Compare NaNs
tap.expect (!almost_equal (0., numeric_limits<double>::quiet_NaN ()), "not almost_equal double 0/NaN");
tap.expect (!almost_equal (numeric_limits<double>::quiet_NaN (), 0.), "not almost_equal double NaN/0");
tap.expect (!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 (!almost_equal (1.0000f, 1.0001f), ".0001f difference inequality");
tap.expect ( almost_equal (1.0000f, 1.00001f), ".00001f difference inequality");
}
void
test_normalisations (util::TAP::logger &tap)
{
// u8 to float
{
auto a = renormalise<uint8_t,float> (255);
tap.expect_eq (a, 1.f, "normalise uint8 max");
auto b = renormalise<uint8_t,float> (0);
tap.expect_eq (b, 0.f, "normalise uint8 min");
}
// float to u8
{
bool success = true;
struct {
float a;
uint8_t b;
} TESTS[] = {
{ 1.f, 255 },
{ 0.f, 0 },
{ 2.f, 255 },
{ -1.f, 0 }
};
for (auto i: TESTS) {
std::cerr << "x";
auto v = renormalise<decltype(i.a),decltype(i.b)> (i.a);
success = success && almost_equal (unsigned{v}, unsigned{i.b});
}
tap.expect (success, "float-u8 normalisation");
}
}
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 (pow2 (4), 16, "pow2");
tap.expect_eq (rootsquare (2, 2), sqrt (8), "rootsquare");
static const double POS_ZERO = 1.0 / numeric_limits<double>::infinity ();
static const double NEG_ZERO = -1.0 / numeric_limits<double>::infinity ();
tap.expect_eq (sign (-1), -1, "sign(-1)");
tap.expect_eq (sign ( 1), 1, "sign( 1)");
tap.expect_eq (sign (POS_ZERO), 1, "sign (POS_ZERO)");
tap.expect_eq (sign (NEG_ZERO), -1, "sign (NEG_ZERO)");
tap.expect_eq (sign ( numeric_limits<double>::infinity ()), 1, "sign +inf");
tap.expect_eq (sign (-numeric_limits<double>::infinity ()), -1, "sign -inf");
tap.expect_eq (to_degrees (PI< float>), 180.f, "to_degrees float");
tap.expect_eq (to_degrees (PI<double>), 180.0, "to_degrees double");
tap.expect_eq (to_radians (180.f), PI<float>, "to_radians float");
tap.expect_eq (to_radians (180.0), PI<double>, "to_radians double");
tap.expect_eq (log2 (8u), 3, "log2 +ve");
tap.expect_eq (log2 (1u), 0, "log2 zero");
//tap.expect_eq (log2 (9u), 3, "log2up 9");
tap.expect_eq (log2up (9u), 4, "log2up 9");
tap.expect_eq (log2up (8u), 3, "log2up 9");
tap.expect_eq (log2up (1u), 0, "log2up 9");
return tap.status ();
}