bpo-39396: Fix math.nextafter(-0.0, +0.0) on AIX 7.1 (GH-18094)
Move also math.nextafter() on math.ulp() tests from IsCloseTests to
MathTests.
diff --git a/Lib/test/test_math.py b/Lib/test/test_math.py
index 6d10227..e96fd74 100644
--- a/Lib/test/test_math.py
+++ b/Lib/test/test_math.py
@@ -1752,6 +1752,83 @@
if not math.isnan(value):
self.fail("Expected a NaN, got {!r}.".format(value))
+ def assertEqualSign(self, x, y):
+ """Similar to assertEqual(), but compare also the sign.
+
+ Function useful to compare signed zeros.
+ """
+ self.assertEqual(x, y)
+ self.assertEqual(math.copysign(1.0, x), math.copysign(1.0, y))
+
+ @requires_IEEE_754
+ def test_nextafter(self):
+ # around 2^52 and 2^63
+ self.assertEqual(math.nextafter(4503599627370496.0, -INF),
+ 4503599627370495.5)
+ self.assertEqual(math.nextafter(4503599627370496.0, INF),
+ 4503599627370497.0)
+ self.assertEqual(math.nextafter(9223372036854775808.0, 0.0),
+ 9223372036854774784.0)
+ self.assertEqual(math.nextafter(-9223372036854775808.0, 0.0),
+ -9223372036854774784.0)
+
+ # around 1.0
+ self.assertEqual(math.nextafter(1.0, -INF),
+ float.fromhex('0x1.fffffffffffffp-1'))
+ self.assertEqual(math.nextafter(1.0, INF),
+ float.fromhex('0x1.0000000000001p+0'))
+
+ # x == y: y is returned
+ self.assertEqual(math.nextafter(2.0, 2.0), 2.0)
+ self.assertEqualSign(math.nextafter(-0.0, +0.0), +0.0)
+ self.assertEqualSign(math.nextafter(+0.0, -0.0), -0.0)
+
+ # around 0.0
+ smallest_subnormal = sys.float_info.min * sys.float_info.epsilon
+ self.assertEqual(math.nextafter(+0.0, INF), smallest_subnormal)
+ self.assertEqual(math.nextafter(-0.0, INF), smallest_subnormal)
+ self.assertEqual(math.nextafter(+0.0, -INF), -smallest_subnormal)
+ self.assertEqual(math.nextafter(-0.0, -INF), -smallest_subnormal)
+ self.assertEqualSign(math.nextafter(smallest_subnormal, +0.0), +0.0)
+ self.assertEqualSign(math.nextafter(-smallest_subnormal, +0.0), -0.0)
+ self.assertEqualSign(math.nextafter(smallest_subnormal, -0.0), +0.0)
+ self.assertEqualSign(math.nextafter(-smallest_subnormal, -0.0), -0.0)
+
+ # around infinity
+ largest_normal = sys.float_info.max
+ self.assertEqual(math.nextafter(INF, 0.0), largest_normal)
+ self.assertEqual(math.nextafter(-INF, 0.0), -largest_normal)
+ self.assertEqual(math.nextafter(largest_normal, INF), INF)
+ self.assertEqual(math.nextafter(-largest_normal, -INF), -INF)
+
+ # NaN
+ self.assertTrue(math.isnan(math.nextafter(NAN, 1.0)))
+ self.assertTrue(math.isnan(math.nextafter(1.0, NAN)))
+ self.assertTrue(math.isnan(math.nextafter(NAN, NAN)))
+
+ @requires_IEEE_754
+ def test_ulp(self):
+ self.assertEqual(math.ulp(1.0), sys.float_info.epsilon)
+ # use int ** int rather than float ** int to not rely on pow() accuracy
+ self.assertEqual(math.ulp(2 ** 52), 1.0)
+ self.assertEqual(math.ulp(2 ** 53), 2.0)
+ self.assertEqual(math.ulp(2 ** 64), 4096.0)
+
+ # min and max
+ self.assertEqual(math.ulp(0.0),
+ sys.float_info.min * sys.float_info.epsilon)
+ self.assertEqual(math.ulp(FLOAT_MAX),
+ FLOAT_MAX - math.nextafter(FLOAT_MAX, -INF))
+
+ # special cases
+ self.assertEqual(math.ulp(INF), INF)
+ self.assertTrue(math.isnan(math.ulp(math.nan)))
+
+ # negative number: ulp(-x) == ulp(x)
+ for x in (0.0, 1.0, 2 ** 52, 2 ** 64, INF):
+ with self.subTest(x=x):
+ self.assertEqual(math.ulp(-x), math.ulp(x))
+
class IsCloseTests(unittest.TestCase):
isclose = math.isclose # subclasses should override this
@@ -2009,83 +2086,6 @@
self.assertIs(type(comb(IntSubclass(5), IntSubclass(k))), int)
self.assertIs(type(comb(MyIndexable(5), MyIndexable(k))), int)
- def assertEqualSign(self, x, y):
- """Similar to assertEqual(), but compare also the sign.
-
- Function useful to compare signed zeros.
- """
- self.assertEqual(x, y)
- self.assertEqual(math.copysign(1.0, x), math.copysign(1.0, y))
-
- @requires_IEEE_754
- def test_nextafter(self):
- # around 2^52 and 2^63
- self.assertEqual(math.nextafter(4503599627370496.0, -INF),
- 4503599627370495.5)
- self.assertEqual(math.nextafter(4503599627370496.0, INF),
- 4503599627370497.0)
- self.assertEqual(math.nextafter(9223372036854775808.0, 0.0),
- 9223372036854774784.0)
- self.assertEqual(math.nextafter(-9223372036854775808.0, 0.0),
- -9223372036854774784.0)
-
- # around 1.0
- self.assertEqual(math.nextafter(1.0, -INF),
- float.fromhex('0x1.fffffffffffffp-1'))
- self.assertEqual(math.nextafter(1.0, INF),
- float.fromhex('0x1.0000000000001p+0'))
-
- # x == y: y is returned
- self.assertEqual(math.nextafter(2.0, 2.0), 2.0)
- self.assertEqualSign(math.nextafter(-0.0, +0.0), +0.0)
- self.assertEqualSign(math.nextafter(+0.0, -0.0), -0.0)
-
- # around 0.0
- smallest_subnormal = sys.float_info.min * sys.float_info.epsilon
- self.assertEqual(math.nextafter(+0.0, INF), smallest_subnormal)
- self.assertEqual(math.nextafter(-0.0, INF), smallest_subnormal)
- self.assertEqual(math.nextafter(+0.0, -INF), -smallest_subnormal)
- self.assertEqual(math.nextafter(-0.0, -INF), -smallest_subnormal)
- self.assertEqualSign(math.nextafter(smallest_subnormal, +0.0), +0.0)
- self.assertEqualSign(math.nextafter(-smallest_subnormal, +0.0), -0.0)
- self.assertEqualSign(math.nextafter(smallest_subnormal, -0.0), +0.0)
- self.assertEqualSign(math.nextafter(-smallest_subnormal, -0.0), -0.0)
-
- # around infinity
- largest_normal = sys.float_info.max
- self.assertEqual(math.nextafter(INF, 0.0), largest_normal)
- self.assertEqual(math.nextafter(-INF, 0.0), -largest_normal)
- self.assertEqual(math.nextafter(largest_normal, INF), INF)
- self.assertEqual(math.nextafter(-largest_normal, -INF), -INF)
-
- # NaN
- self.assertTrue(math.isnan(math.nextafter(NAN, 1.0)))
- self.assertTrue(math.isnan(math.nextafter(1.0, NAN)))
- self.assertTrue(math.isnan(math.nextafter(NAN, NAN)))
-
- @requires_IEEE_754
- def test_ulp(self):
- self.assertEqual(math.ulp(1.0), sys.float_info.epsilon)
- # use int ** int rather than float ** int to not rely on pow() accuracy
- self.assertEqual(math.ulp(2 ** 52), 1.0)
- self.assertEqual(math.ulp(2 ** 53), 2.0)
- self.assertEqual(math.ulp(2 ** 64), 4096.0)
-
- # min and max
- self.assertEqual(math.ulp(0.0),
- sys.float_info.min * sys.float_info.epsilon)
- self.assertEqual(math.ulp(FLOAT_MAX),
- FLOAT_MAX - math.nextafter(FLOAT_MAX, -INF))
-
- # special cases
- self.assertEqual(math.ulp(INF), INF)
- self.assertTrue(math.isnan(math.ulp(math.nan)))
-
- # negative number: ulp(-x) == ulp(x)
- for x in (0.0, 1.0, 2 ** 52, 2 ** 64, INF):
- with self.subTest(x=x):
- self.assertEqual(math.ulp(-x), math.ulp(x))
-
def test_main():
from doctest import DocFileSuite