@brief random number generator to use
`--random.generator arg`

The argument is an integer (1,2,3 or 4) which sets the manner in which
random numbers are generated. The default method (3) is to use the a
non-blocking random (or pseudorandom) number generator supplied by the
operating system.

Specifying an argument of 2, uses a blocking random (or
pseudorandom) number generator. Specifying an argument 1 sets a
pseudorandom
number generator using an implication of the Mersenne Twister MT19937
algorithm. Algorithm 4 is a combination of the blocking random number
generator and the Mersenne Twister.