Determining the machine-epsilon

Solution P9.1.2

For example:

def get_epsilon(dtype):
    eps = dtype(1)
    while dtype(1) + dtype(eps) != dtype(1):
        previous_eps = eps
        eps = dtype(eps) / dtype(2)
    return previous_eps

print(int, get_epsilon(int))
print(float, get_epsilon(float))

import numpy as np
print(np.float128, get_epsilon(np.float128))

Gives, on my system:

<class 'int'> 1
<class 'float'> 2.220446049250313e-16
<class 'numpy.float128'> 1.08420217249e-19