python: getting around division by zero

Question

I have a big data set of floating point numbers. I iterate through them and evaluate np.log(x) for each of them. I get

RuntimeWarning: divide b         


        

Answer 1

I like to use sys.float_info.min as follows:

>>> import numpy as np
>>> import sys
>>> arr = np.linspace(0.0, 1.0, 3)
>>> print(arr)
[0.  0.5 1. ]
>>> arr[arr < sys.float_info.min] = sys.float_info.min
>>> print(arr)
[2.22507386e-308 5.00000000e-001 1.00000000e+000]
>>> np.log10(arr)
array([-3.07652656e+02, -3.01029996e-01,  0.00000000e+00])

Other answers have also introduced introduced small positive values, but I prefer to use the smallest valid input when I am approximating the result for an input that is too small to be processed.