/* -------------------------------------------------------------------------
 * This is an ANSI C library for multi-stream random number generation.  
 * The use of this library is recommended as a replacement for the ANSI C 
 * rand() and srand() functions, particularly in simulation applications 
 * where the statistical 'goodness' of the random number generator is 
 * important.  The library supplies 256 streams of random numbers; use 
 * SelectStream(s) to switch between streams indexed s = 0,1,...,255.
 *
 * The streams must be initialized.  The recommended way to do this is by
 * using the function PlantSeeds(x) with the value of x used to initialize 
 * the default stream and all other streams initialized automatically with
 * values dependent on the value of x.  The following convention is used 
 * to initialize the default stream:
 *    if x > 0 then x is the state
 *    if x < 0 then the state is obtained from the system clock
 *    if x = 0 then the state is to be supplied interactively.
 *
 * The generator used in this library is a so-called 'Lehmer random number
 * generator' which returns a pseudo-random number uniformly distributed
 * 0.0 and 1.0.  The period is (m - 1) where m = 2,147,483,647 and the
 * smallest and largest possible values are (1 / m) and 1 - (1 / m)
 * respectively.  For more details see:
 * 
 *       "Random Number Generators: Good Ones Are Hard To Find"
 *                   Steve Park and Keith Miller
 *              Communications of the ACM, October 1988
 *
 * Name            : rngs.c  (Random Number Generation - Multiple Streams)
 * Authors         : Steve Park & Dave Geyer
 * Language        : ANSI C
 * Latest Revision : 09-22-98
 * ------------------------------------------------------------------------- 
 */

#include <stdio.h>
#include <time.h>
#include <stdlib.h>
#include "rngs.h"

#define MODULUS    2147483647 /* DON'T CHANGE THIS VALUE                  */
#define MULTIPLIER 48271      /* DON'T CHANGE THIS VALUE                  */
#define CHECK      399268537  /* DON'T CHANGE THIS VALUE                  */
#define STREAMS    256        /* # of streams, DON'T CHANGE THIS VALUE    */
#define A256       22925      /* jump multiplier, DON'T CHANGE THIS VALUE */
#define DEFAULT    123456789  /* initial seed, use 0 < DEFAULT < MODULUS  */

static long seed[STREAMS] = {DEFAULT};  /* current state of each stream   */
static int  stream        = 0;          /* stream index, 0 is the default */
static int  initialized   = 0;          /* test for stream initialization */



float frand(float from, float to)
{
    /*
    int r = random();
    int q = r%(to-from);
    
    
    return (float)r-q*(to-from)+from;
     */
    
    return (float)(((double)random()/RAND_MAX)*(to-from)+from);
}

int irand(int from, int to)
{
    //srand(time(NULL));
    
    return (int)(((double)random()/RAND_MAX)*(to-from+1)+from);
}

int signrand()
{
    return irand(0, 1)*2-1;
}