Random Numbers Generator (CGAL_Random)

Definition

Instances of CGAL_Random can be seen as input streams. Different streams are independent of each other, i.e. the sequence of numbers from one stream does not depend upon how many numbers were extracted from the other streams.

It can be very useful, e.g. for debugging, to reproduce a sequence of random numbers. This can be done by either initializing deterministically or using the seed functions as described below.

#include <CGAL/Random.h>

Global Variables

CGAL_Random

CGAL_random;

This global variable is used as the default random numbers generator.

Types

CGAL_Random::Seed
	Seed type.

Creation

CGAL_Random random;
	introduces a variable random of type CGAL_Random.
CGAL_Random random ( Seed seed);
	introduces a variable random of type CGAL_Random and initializes its internal seed with seed.
CGAL_Random random ( long init);
	introduces a variable random of type CGAL_Random and initializes its internal seed using init. Equal values for init result in equal sequences of random numbers.

Operations

bool	random.get_bool ()	returns a random bool.
int	random.get_int ( int lower, int upper)
		returns a random int from the interval $[$lower,upper$)$.
double	random.get_double ( double lower = 0.0, double upper = 1.0)
		returns a random double from $[$lower,upper$)$.
int	random ( int upper)
		returns random.get_int( 0, upper).

Seed Functions

void	random.save_seed ( Seed& seed)
		saves the current internal seed in seed.
void	random.restore_seed ( Seed seed)
		restores the internal seed from seed.

Equality Test

bool

random == random2

returns true, iff random and random2 have equal internal seeds.

Implementation