BUG: incorrect promotion for Python integer inputs in ldexp #29182
Description
Describe the issue:
Depending on the input types, the return value of ldexp raises an overflow or returns "infinity", while the same call with python integers just works.
Reproduce the code example:
>>> import numpy as np
# this should work: note the return type should not be float16 in this case.
>>> np.ldexp(1, np.int32(16))
<stdin>:1: RuntimeWarning: overflow encountered in ldexp
np.float16(inf)
# this should work, interestingly I do not see the overflow
>>> np.ldexp(1, np.int64(16))
np.float16(inf)
# ok, this is float
>>> np.ldexp(1., np.int64(16))
np.float64(65536.0)
# this just works fine
>>> np.ldexp(1, int(16))
np.float64(65536.0)Error message:
See above.Python and NumPy Versions:
- python3.10
- numpy2.2.6, conda hash
py310hefbff90_0
Runtime Environment:
>>> import numpy; numpy.show_runtime()
[{'numpy_version': '2.2.6',
'python': '3.10.18 | packaged by conda-forge | (main, Jun 4 2025, 14:45:41) '
'[GCC 13.3.0]',
'uname': uname_result(system='Linux', node='odin', release='6.1.0-32-amd64', version='#1 SMP PREEMPT_DYNAMIC Debian 6.1.129-1 (2025-03-06)', machine='x86_64')},
{'simd_extensions': {'baseline': ['SSE', 'SSE2', 'SSE3'],
'found': ['SSSE3',
'SSE41',
'POPCNT',
'SSE42',
'AVX',
'F16C',
'FMA3',
'AVX2'],
'not_found': ['AVX512F',
'AVX512CD',
'AVX512_KNL',
'AVX512_KNM',
'AVX512_SKX',
'AVX512_CLX',
'AVX512_CNL',
'AVX512_ICL',
'AVX512_SPR']}}]
Context for the issue:
Code that used to work with previous versions of python now breaks, with a trivial workaround.