Pseudo-random number generator (PRNG).
Initialize the generator, using the argument as a seed. The same seed will always yield the same sequence of numbers.
Initialize the generator with a more-or-less random seed chosen in a system-dependent way.
Return 30 random bits in a nonnegative integer.
Values of this type are used to store the current state of the generator.
val get_state :
Returns the current state of the generator. This is useful for checkpointing computations that use the PRNG.
val set_state :
Resets the state of the generator to some previous state returned by