second smallest number in python code example

Example: smallest possible number in python

The smallest possible number in python (not underflow to 0)
is the smallest possible subnormal number.

# L is the lowerbound exponent given by IEEE754 double precision.
L_sub < (machine_epsilon * 2**L)  =  (2**-52) * (2**-1022) = 2**-1074

Thus, smallest_number = 2*-1074 => 5e-324