python numpy machine epsilon
An easier way to get the machine epsilon for a given float type is to use np.finfo():
print(np.finfo(float).eps)
# 2.22044604925e-16
print(np.finfo(np.float32).eps)
# 1.19209e-07
Another easy way to get epsilon is:
In [1]: 7./3 - 4./3 -1
Out[1]: 2.220446049250313e-16