25.1.3.1 Member Functions

The random number generator is implemented by the RNG class and is defined in tools/rng.h.

Note: The Random class in tools/random.h is an older interface to the standard random number stream.

Member functions provide the following operations:

void set_seed (long seed)

- set the seed of the RNG, if $seed == 0$, the seed is set according to the current time and a counter

long seed (void)

- return the current seed

long next (void)

- return the next random number as an integer on [0, MAXINT]

double next_double (void)

- return the next random number on [0, 1]

void reset_start_substream (void)

- reset the stream to the beginning of the current substream

void reset_next_substream (void)

- advance to the next substream

int uniform (int k)

- return an integer sampled from a uniform distribution on [0, k-1]

double uniform (double r)

- return a number sampled from a uniform distribution on [0, r]

double uniform (double a, double b)

- return a number sampled from a uniform distribution on [a, b]

double exponential (void)

- return a number sampled from an exponential distribution with mean 1.0

double exponential (double k)

- return a number sampled from an exponential distribution with mean k

double normal (double avg, double std)

- return a number sampled from a normal distribution with the given average and standard deviation

double lognormal (double avg, double std)

- return a number sampled from a lognormal distribution with the given average and standard deviation