Ignore divide by 0 warning in NumPy
PythonNumpySuppress WarningsDivide by-ZeroPython Problem Overview
I have a function for statistic issues:
import numpy as np
from scipy.special import gamma as Gamma
def Foo(xdata):
...
return x1 * (
( #R is a numpy vector
( ((R - x2)/beta) ** (x3 -1) ) *
( np.exp( - ((R - x2) / x4) ) ) /
( x4 * Gamma(x3))
).real
)
Sometimes I get from the shell the following warning:
RuntimeWarning: divide by zero encountered in...
I use the numpy isinf
function to correct the results of the function in other files, so I do not need this warning.
Is there a way to ignore the message? In other words, I do not want the shell to print this message.
I do not want to disable all python warnings, just this one.
Python Solutions
Solution 1 - Python
You can disable the warning with numpy.seterr
. Put this before the possible division by zero:
np.seterr(divide='ignore')
That'll disable zero division warnings globally. If you just want to disable them for a little bit, you can use numpy.errstate
in a with
clause:
with np.errstate(divide='ignore'):
# some code here
For a zero by zero division (undetermined, results in a NaN), the error behaviour has changed with numpy version 1.12.0: this is now considered "invalid", while previously it was "divide".
Thus, if there is a chance you your numerator could be zero as well, use
np.seterr(divide='ignore', invalid='ignore')
or
with np.errstate(divide='ignore', invalid='ignore'):
# some code here
See the "Compatibility" section in the release notes, last paragraph before the "New Features" section:
> Comparing NaN floating point numbers now raises the invalid runtime warning. If a NaN is expected the warning can be ignored using np.errstate.
Solution 2 - Python
You could also use numpy.divide
for division. That way you don't have to explicitly disable warnings.
In [725]: np.divide(2, 0)
Out[725]: 0