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| author | Mark Dickinson <mdickinson@enthought.com> | 2019-12-09 14:36:34 (GMT) |
|---|---|---|
| committer | GitHub <noreply@github.com> | 2019-12-09 14:36:34 (GMT) |
| commit | bba873e633f0f1e88ea12fb935cbd58faa77f976 (patch) | |
| tree | 5cb3c02fad1450c50e0842c35e75a36a18c0b30d /Lib/test | |
| parent | ab513a38c98695f271e448fe2cb7c5e39eeaaaaf (diff) | |
| download | cpython-bba873e633f0f1e88ea12fb935cbd58faa77f976.zip cpython-bba873e633f0f1e88ea12fb935cbd58faa77f976.tar.gz cpython-bba873e633f0f1e88ea12fb935cbd58faa77f976.tar.bz2 | |
bpo-38992: avoid fsum test failure from constant-folding (GH-17513)
* Issue 38992: avoid fsum test failure
* Add NEWS entry
Diffstat (limited to 'Lib/test')
| -rw-r--r-- | Lib/test/test_math.py | 8 |
1 files changed, 7 insertions, 1 deletions
diff --git a/Lib/test/test_math.py b/Lib/test/test_math.py index f832246..5c35c8c 100644 --- a/Lib/test/test_math.py +++ b/Lib/test/test_math.py @@ -676,7 +676,6 @@ class MathTests(unittest.TestCase): float.fromhex('0x1.df11f45f4e61ap+2')), ([(-1.)**n/n for n in range(1, 1001)], float.fromhex('-0x1.62a2af1bd3624p-1')), - ([1.7**(i+1)-1.7**i for i in range(1000)] + [-1.7**1000], -1.0), ([1e16, 1., 1e-16], 10000000000000002.0), ([1e16-2., 1.-2.**-53, -(1e16-2.), -(1.-2.**-53)], 0.0), # exercise code for resizing partials array @@ -685,6 +684,13 @@ class MathTests(unittest.TestCase): float.fromhex('0x1.5555555555555p+970')), ] + # Telescoping sum, with exact differences (due to Sterbenz) + terms = [1.7**i for i in range(1001)] + test_values.append(( + [terms[i+1] - terms[i] for i in range(1000)] + [-terms[1000]], + -terms[0] + )) + for i, (vals, expected) in enumerate(test_values): try: actual = math.fsum(vals) |