gh-119372: Recover inf's and zeros in _Py_c_quot (GH-119457)

In some cases, previously computed as (nan+nanj), we could
recover meaningful component values in the result, see
e.g. the C11, Annex G.5.2, routine _Cdivd().
This commit is contained in:
Sergey B Kirpichev 2024-06-29 11:00:48 +03:00 committed by GitHub
parent 0a1e8ff9c1
commit 2cb84b107a
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3 changed files with 56 additions and 2 deletions

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@ -94,6 +94,10 @@ class ComplexTest(unittest.TestCase):
msg += ': zeros have different signs'
self.fail(msg.format(x, y))
def assertComplexesAreIdentical(self, x, y):
self.assertFloatsAreIdentical(x.real, y.real)
self.assertFloatsAreIdentical(x.imag, y.imag)
def assertClose(self, x, y, eps=1e-9):
"""Return true iff complexes x and y "are close"."""
self.assertCloseAbs(x.real, y.real, eps)
@ -139,6 +143,33 @@ class ComplexTest(unittest.TestCase):
self.assertTrue(isnan(z.real))
self.assertTrue(isnan(z.imag))
self.assertComplexesAreIdentical(complex(INF, 1)/(0.0+1j),
complex(NAN, -INF))
# test recover of infs if numerator has infs and denominator is finite
self.assertComplexesAreIdentical(complex(INF, -INF)/(1+0j),
complex(INF, -INF))
self.assertComplexesAreIdentical(complex(INF, INF)/(0.0+1j),
complex(INF, -INF))
self.assertComplexesAreIdentical(complex(NAN, INF)/complex(2**1000, 2**-1000),
complex(INF, INF))
self.assertComplexesAreIdentical(complex(INF, NAN)/complex(2**1000, 2**-1000),
complex(INF, -INF))
# test recover of zeros if denominator is infinite
self.assertComplexesAreIdentical((1+1j)/complex(INF, INF), (0.0+0j))
self.assertComplexesAreIdentical((1+1j)/complex(INF, -INF), (0.0+0j))
self.assertComplexesAreIdentical((1+1j)/complex(-INF, INF),
complex(0.0, -0.0))
self.assertComplexesAreIdentical((1+1j)/complex(-INF, -INF),
complex(-0.0, 0))
self.assertComplexesAreIdentical((INF+1j)/complex(INF, INF),
complex(NAN, NAN))
self.assertComplexesAreIdentical(complex(1, INF)/complex(INF, INF),
complex(NAN, NAN))
self.assertComplexesAreIdentical(complex(INF, 1)/complex(1, INF),
complex(NAN, NAN))
def test_truediv_zero_division(self):
for a, b in ZERO_DIVISION:
with self.assertRaises(ZeroDivisionError):