BUG: numpy RuntimeWarning with Series.round()

[xflr6]

Maybe needs wrapping in numpy.errstate (in pandas)?

>>> import pandas as pd
>>> pd.__version__
u'0.19.0rc1'
>>> pd.Series([pd.np.nan]).round()

Warning (from warnings module):
  File "C:\Program Files\Python27\lib\site-packages\pandas\core\series.py", line 1340
    result = _values_from_object(self).round(decimals)
RuntimeWarning: invalid value encountered in rint
0   NaN
dtype: float64

Same for DataFrame.round().

[jreback]

need to mask the values before rounding (iow not null ones)

[tom-bird]

I'll have a look and submit a PR

[tom-bird]

I can't seem to replicate the warning..

Running 2.7.12 and the latest dev version of pandas

[jreback]

hmm, maybe this is on an older version of numpy.

@xflr6 can you pd.show_versions() where you got that error

[xflr6]

Sure:

>>> import pandas as pd
>>> pd.Series([pd.np.nan]).round()

Warning (from warnings module):
  File "C:\Program Files\Python27\lib\site-packages\pandas\core\series.py", line 1340
    result = _values_from_object(self).round(decimals)
RuntimeWarning: invalid value encountered in rint
0   NaN
dtype: float64
>>> pd.show_versions()

INSTALLED VERSIONS
------------------
commit: None
python: 2.7.12.final.0
python-bits: 64
OS: Windows
OS-release: 7
machine: AMD64
processor: Intel64 Family 6 Model 42 Stepping 7, GenuineIntel
byteorder: little
LC_ALL: None
LANG: None
LOCALE: de_DE.cp1252

pandas: 0.19.0rc1
nose: 1.3.7
pip: 8.1.2
setuptools: 27.2.0
Cython: 0.24.1
numpy: 1.11.1
scipy: 0.18.0
statsmodels: 0.8.0rc1
xarray: None
IPython: 5.1.0
sphinx: 1.4.6
patsy: 0.4.1
dateutil: 2.5.3
pytz: 2016.6.1
blosc: None
bottleneck: 1.1.0
tables: None
numexpr: 2.6.1
matplotlib: 1.5.3
openpyxl: 2.4.0
xlrd: 1.0.0
xlwt: None
xlsxwriter: None
lxml: 3.6.4
bs4: 4.5.1
html5lib: 0.999999999
httplib2: 0.9.2
apiclient: None
sqlalchemy: 1.0.15
pymysql: None
psycopg2: 2.6.2 (dt dec pq3 ext lo64)
jinja2: 2.8
boto: None
pandas_datareader: None

In some environments, warnings are silenced, try this before:

>>> import warnings
>>> warnings.simplefilter('error')

[xflr6]

Seems to be a Windows-specific upstream issue: numpy/numpy#7882

>>> import numpy as np
>>> np.ma.masked_invalid([np.nan]).round()

Warning (from warnings module):
  File "C:\Program Files\Python27\lib\site-packages\numpy\ma\core.py", line 5192
    result = self._data.round(decimals=decimals, out=out).view(type(self))
RuntimeWarning: invalid value encountered in rint
masked_array(data = [--],
             mask = [ True],
       fill_value = 1e+20)

>>> np.rint(np.nan)

Warning (from warnings module):
  File "__main__", line 2
RuntimeWarning: invalid value encountered in rint
nan