Closed
Description
This investigation arises from scipy CI starting to fail on appveyor in the last few days, i.e. after 1.14 being released.
On my home computer (macOS, conda python 3.6.2, conda numpy):
>>> import numpy as np
>>> np.version.version
'1.14.0'
>>> np.min([1.0, 2.0, np.nan])
nan
>>> np.min([1.0, np.nan, 2.0])
nan
>>> np.min([np.nan, 1.0, 2.0])
nan
>>> np.min([np.nan, 1.0])
/Users/andrew/miniconda3/envs/dev3/lib/python3.6/site-packages/numpy/core/_methods.py:29: RuntimeWarning: invalid value encountered in reduce
return umr_minimum(a, axis, None, out, keepdims)
nan
On my work computer (macOS, conda python 3.6.2, numpy installed via pip in a clean env):
>>> import numpy as np
>>> np.version.version
'1.14.0'
>>> np.min([1., 2., 3., 4., np.nan])
nan
>>> np.min([1., 2., 3., np.nan, 4.])
nan
>>> np.min([1., 2., np.nan, 3., 4.])
nan
>>> np.min([1., np.nan, 2., 3., 4.])
nan
>>> np.min([np.nan, 1., 2., 3., 4.])
nan
>>> np.min([np.nan, 1.])
nan
>>> np.min([np.nan, 1., np.nan])
nan
>>> np.min([1., np.nan])
nan
>>> np.seterr(all='raise')
{'divide': 'warn', 'over': 'warn', 'under': 'ignore', 'invalid': 'warn'}
>>> np.min([1., np.nan])
nan
>>> np.min([np.nan, 1.])
nan
>>> np.min([np.nan, 1., 2., 3., 4.])
nan
>>> np.min([np.nan, 1., 2., 3., 4.])
nan
With the first set of code examples why don't the first three examples result in a warning, only the last?
With the second set of examples no warning is emitted at all.