n must be an exact positive integer. random returns an exact integer between zero (inclusive) and n (exclusive). The values returned by random are uniformly distributed from 0 to n.

The optional argument state must be of the type returned by (seed->random-state) or (make-random-state). It defaults to the value of the variable *random-state*. This object is used to maintain the state of the pseudo-random-number generator and is altered as a side effect of calls to random.

Holds a data structure that encodes the internal state of the random-number generator that random uses by default. The nature of this data structure is implementation-dependent. It may be printed out and successfully read back in, but may or may not function correctly as a random-number state object in another implementation.

Returns a new copy of argument state.

Returns a new copy of *random-state*.

Returns a new object of type suitable for use as the value of the variable *random-state* or as a second argument to random. The number or string seed is used to initialize the state. If seed->random-state is called twice with arguments which are equal?, then the returned data structures will be equal?. Calling seed->random-state with unequal arguments will nearly always return unequal states.

Returns a new object of type suitable for use as the value of the variable *random-state* or as a second argument to random. If the optional argument obj is given, it should be a printable Scheme object; the first 50 characters of its printed representation will be used as the seed. Otherwise the value of *random-state* is used as the seed.

Returns an uniformly distributed inexact real random number in the range between 0 and 1.

Returns an inexact real in an exponential distribution with mean 1. For an exponential distribution with mean u use (* u (random:exp)).

Returns an inexact real in a normal distribution with mean 0 and standard deviation 1. For a normal distribution with mean m and standard deviation d use (+ m (* d (random:normal))).

Fills vect with inexact real random numbers which are independent and standard normally distributed (i.e., with mean 0 and variance 1).

Fills vect with inexact real random numbers the sum of whose squares is equal to 1.0. Thinking of vect as coordinates in space of dimension n = (vector-length vect), the coordinates are uniformly distributed over the surface of the unit n-shere.

Fills vect with inexact real random numbers the sum of whose squares is less than 1.0. Thinking of vect as coordinates in space of dimension n = (vector-length vect), the coordinates are uniformly distributed within the unit n-shere. The sum of the squares of the numbers is returned.