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Merged
picnixz merged 10 commits into from
Sep 9, 2026
Merged

gh-155966: Correct handling of math.tanpi poles #155980

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886d4ac
gh-155966: Correct handling of tanpi(0.5) (#155966)
jepler Aug 17, 2026
faa1799
math_testcases: Fix duplicate test ids
jepler Aug 17, 2026
198937d
test_math: Treat duplicate test ids as failure.
jepler Aug 17, 2026
5bd16b9
Add news entry
jepler Aug 17, 2026
e59375b
Update Misc/NEWS.d/next/Library/2026-08-17-17-39-41.gh-issue-155966.0…
jepler Aug 18, 2026
9dff17a
fix sign of infinity in test cases
jepler Aug 18, 2026
b4b4484
Revert "math_testcases: Fix duplicate test ids"
jepler Aug 18, 2026
38f4d61
fix only minimal set of testcase IDs
jepler Aug 18, 2026
216f1da
Apply suggestion from @skirpichev
skirpichev Aug 18, 2026
f7a4d0a
Merge branch 'main' into issue-155966
skirpichev Aug 19, 2026
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59 changes: 32 additions & 27 deletions Lib/test/mathdata/math_testcases.txt
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Original file line number Diff line number Diff line change
Expand Up @@ -1311,45 +1311,45 @@ atan2pi20000 atan2pi inf 0 -> 0.5
atan2pi20001 atan2pi -inf 0 -> -0.5
atan2pi20002 atan2pi nan 0 -> nan

atan2pi20000 atan2pi inf -0 -> 0.5
atan2pi20001 atan2pi -inf -0 -> -0.5
atan2pi20002 atan2pi nan -0 -> nan
atan2pi21000 atan2pi inf -0 -> 0.5
atan2pi21001 atan2pi -inf -0 -> -0.5
atan2pi21002 atan2pi nan -0 -> nan

atan2pi20003 atan2pi inf 1 -> 0.5
atan2pi20004 atan2pi -inf 1 -> -0.5
atan2pi20005 atan2pi nan 1 -> nan
atan2pi22003 atan2pi inf 1 -> 0.5
atan2pi22004 atan2pi -inf 1 -> -0.5
atan2pi22005 atan2pi nan 1 -> nan
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atan2pi20006 atan2pi inf -1 -> 0.5
atan2pi20007 atan2pi -inf -1 -> -0.5
atan2pi20008 atan2pi nan -1 -> nan
atan2pi23006 atan2pi inf -1 -> 0.5
atan2pi23007 atan2pi -inf -1 -> -0.5
atan2pi23008 atan2pi nan -1 -> nan

atan2pi20009 atan2pi inf inf -> 0.25
atan2pi20010 atan2pi -inf inf -> -0.25
atan2pi20011 atan2pi nan inf -> nan
atan2pi24009 atan2pi inf inf -> 0.25
atan2pi24010 atan2pi -inf inf -> -0.25
atan2pi24011 atan2pi nan inf -> nan

atan2pi20012 atan2pi inf -inf -> .75
atan2pi20013 atan2pi -inf -inf -> -.75
atan2pi20014 atan2pi nan -inf -> nan
atan2pi25012 atan2pi inf -inf -> .75
atan2pi25013 atan2pi -inf -inf -> -.75
atan2pi25014 atan2pi nan -inf -> nan

atan2pi20015 atan2pi inf nan -> nan
atan2pi20016 atan2pi -inf nan -> nan
atan2pi20017 atan2pi nan nan -> nan
atan2pi26015 atan2pi inf nan -> nan
atan2pi26016 atan2pi -inf nan -> nan
atan2pi26017 atan2pi nan nan -> nan

atan2pi30000 atan2pi 0 inf -> 0.0
atan2pi30001 atan2pi 0 -inf -> 1.0
atan2pi30002 atan2pi 0 nan -> nan

atan2pi30000 atan2pi -0 inf -> -0.0
atan2pi30001 atan2pi -0 -inf -> -1.0
atan2pi30002 atan2pi -0 nan -> nan
atan2pi31000 atan2pi -0 inf -> -0.0
atan2pi31001 atan2pi -0 -inf -> -1.0
atan2pi31002 atan2pi -0 nan -> nan

atan2pi30003 atan2pi 1 inf -> 0.0
atan2pi30004 atan2pi 1 -inf -> 1.0
atan2pi30005 atan2pi 1 nan -> nan
atan2pi32003 atan2pi 1 inf -> 0.0
atan2pi32004 atan2pi 1 -inf -> 1.0
atan2pi32005 atan2pi 1 nan -> nan

atan2pi30006 atan2pi -1 inf -> -0.0
atan2pi30007 atan2pi -1 -inf -> -1.0
atan2pi30008 atan2pi -1 nan -> nan
atan2pi33006 atan2pi -1 inf -> -0.0
atan2pi33007 atan2pi -1 -inf -> -1.0
atan2pi33008 atan2pi -1 nan -> nan

-----------
-- cospi --
Expand Down Expand Up @@ -2247,3 +2247,8 @@ tanpi10275 tanpi -1.6591963470121216 -> 1.829921944286168
tanpi20001 tanpi inf -> nan invalid
tanpi20002 tanpi -inf -> nan invalid
tanpi20003 tanpi nan -> nan

tanpi30050 tanpi 0.5 -> inf invalid
tanpi30055 tanpi -0.5 -> inf invalid
tanpi30115 tanpi 1.5 -> inf invalid
tanpi30118 tanpi -1.5 -> inf invalid
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5 changes: 5 additions & 0 deletions Lib/test/test_math.py
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Expand Up @@ -2144,7 +2144,12 @@ def test_mtestfile(self):
fail_fmt = "{}: {}{!r}: {}"

failures = []
ids = set()
for id, fn, args, expected, flags in parse_mtestfile(math_testcases):
if id in ids:
failures.append(f"Duplicate test id {id}")
ids.add(id)

func = getattr(math, fn)

if 'invalid' in flags or 'divide-by-zero' in flags:
Expand Down
2 changes: 2 additions & 0 deletions Misc/NEWS.d/next/Library/2026-08-17-17-39-41.gh-issue-155966.0YOADY.rst
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@@ -0,0 +1,2 @@
:func:`math.atanpi` now raises :exc:`ValueError` for half-integer values
(e.g., ``atanpi(1.5)``), as these are poles of the function.
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4 changes: 2 additions & 2 deletions Modules/mathmodule.c
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Expand Up @@ -1343,10 +1343,10 @@ FUNC1D(tan, tan, 0,
FUNC1(tanh, tanh, 0,
"tanh($module, x, /)\n--\n\n"
"Return the hyperbolic tangent of x.")
FUNC1D(tanpi, m_tanpi, 1,
FUNC1D(tanpi, m_tanpi, 0,
"tanpi($module, x, /)\n--\n\n"
"Return the tangent of x (measured in half-turns).",
"expected a finite input, got %s")
"expected a finite input not equal to a half-integer, got %s")

/* Precision summation function as msum() by Raymond Hettinger in
<https://code.activestate.com/recipes/393090-binary-floating-point-summation-accurate-to-full-p/>,
Expand Down
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