/* RAND.H - Interface to random number generation procedures. *//* Copyright (c) 1995, 2000, 2001 by Radford M. Neal  * * Permission is granted for anyone to copy, use, or modify this program  * for purposes of research or education, provided this copyright notice  * is retained, and note is made of any changes that have been made.  * * This program is distributed without any warranty, express or implied. * As this program was written for research purposes only, it has not been * tested to the degree that would be advisable in any important application. * All use of this program is entirely at the user's own risk. *//* STATE OF RANDOM NUMBER GENERATOR. */#define N_tables 5		/* Number of tables of real random numbers */typedef struct{ int seed;			/* Seed state derives from */  int ptr[N_tables];		/* Pointers for tables of real random numbers */  unsigned short state48[3];	/* State of 'rand48' pseudo-random generator */} rand_state;/* BASIC PSEUDO-RANDOM GENERATION PROCEDURES. */void rand_seed (int);		/* Initialize current state structure by seed */void rand_use_state (rand_state *); /* Start using given state structure */rand_state *rand_get_state (void);  /* Return pointer to current state */int rand_word (void);		/* Generate random 31-bit positive integer *//* GENERATORS FOR VARIOUS DISTRIBUTIONS. */double rand_uniform (void);	/* Uniform from [0,1) */double rand_uniopen (void);	/* Uniform from (0,1) */int rand_int (int);		/* Uniform from 0, 1, ... (n-1) */int rand_pickd (double *, int);	/* From 0 ... (n-1), with given distribution */int rand_pickf (float *, int);	/* Same as above, but with floats */double rand_gaussian (void);	/* Gaussian with mean zero and unit variance */double rand_logistic (void);	/* Logistic centred at zero with unit width */double rand_cauchy (void);	/* Cauchy centred at zero with unit width */double rand_gamma (double);	/* Gamma with given shape parameter */double rand_exp (void);		/* Exponential with mean one */double rand_beta (double, double); /* Beta with given parameters */