Random number generator

The behavior of the built-in function rand(x) has changed as of version 3.8l. Older scripts that expected rand(x6#60) to produce sequential pseudo-random numbers from the same seeded sequence must be changed to call rand(0) instead. The current behavior is as follows:

`rand(0)`  returns a pseudo random number in the interval [0:1] generated
           from the current value of two internal 32-bit seeds.
`rand(-1)` resets both seeds to a standard value.
`rand(x)`  for x>0 sets both seeds to a value based on the value of x.
`rand({x,y})` for x>0 sets seed1 to x and seed2 to y.