sigmoid RuntimeWarning: overflow encountered in exp

Question

I\'m trying to create a sigmoid function in Python, however, I get the following error:

RuntimeWarning: overflow encountered in exp

Here my

Answer 1

A warning is not an error. You could just ignore it.

That said, it happens when the result of exp(-value) exceeds the maximum number representable by value's floating point data type format.

You can prevent the overflow by checking if value is too small:

def sigmoid(value):
    if -value > np.log(np.finfo(type(value)).max):
        return 0.0    
    a = np.exp(-value)
    return 1.0/ (1.0 + a)