Bug report
Bug description:
The math function atan2 and the cmath function phase should not raise ValueError when their arguments are zero. This is true when building CPython using an officially supported compiler such as GCC:
>>> import math
>>> import cmath
>>> math.atan2(0.0, 0.0)
0.0
>>> cmath.phase(complex(0.0, 0.0))
0.0
>>> math.atan2(0.0, -0.0)
3.141592653589793
>>> cmath.phase(complex(-0.0, 0.0))
3.141592653589793
However, The C23 standard (ISO/IEC 9899:2024) in section 7.12.4.4 for atan2 states:
A domain error may occur if both arguments are zero.
The Intel math library version 2026.0.0 sets errno to EDOM for these cases. See also PR #152825. Thus:
>>> import math
>>> import cmath
>>> math.atan2(0.0, 0.0)
Traceback (most recent call last):
File "<python-input-2>", line 1, in <module>
math.atan2(0.0, 0.0)
~~~~~~~~~~^^^^^^^^^^
ValueError: math domain error
>>> cmath.phase(complex(0.0, 0.0))
Traceback (most recent call last):
File "<python-input-3>", line 1, in <module>
cmath.phase(complex(0.0, 0.0))
~~~~~~~~~~~^^^^^^^^^^^^^^^^^^^
ValueError: math domain error
>>> math.atan2(0.0, -0.0)
Traceback (most recent call last):
File "<python-input-4>", line 1, in <module>
math.atan2(0.0, -0.0)
~~~~~~~~~~^^^^^^^^^^^
ValueError: math domain error
>>> cmath.phase(complex(-0.0, 0.0))
Traceback (most recent call last):
File "<python-input-5>", line 1, in <module>
cmath.phase(complex(-0.0, 0.0))
~~~~~~~~~~~^^^^^^^^^^^^^^^^^^^^
ValueError: math domain errorCPython versions tested on:
CPython main branch
Operating systems tested on:
Linux
Linked PRs
Bug report
Bug description:
The math function
atan2and the cmath functionphaseshould not raise ValueError when their arguments are zero. This is true when building CPython using an officially supported compiler such as GCC:However, The C23 standard (ISO/IEC 9899:2024) in section 7.12.4.4 for
atan2states:The Intel math library version 2026.0.0 sets
errnotoEDOMfor these cases. See also PR #152825. Thus:CPython versions tested on:
CPython main branch
Operating systems tested on:
Linux
Linked PRs
errnoforatan2#153148