/* lran2.h

 * by Wolfram Gloger 1996.

 *

 * A small, portable pseudo-random number generator.

 */

#ifndef _LRAN2_H

#define _LRAN2_H

#define LRAN2_MAX 714025l /* constants for portable */

#define IA	  1366l	  /* random number generator */

#define IC	  150889l /* (see e.g. `Numerical Recipes') */

struct lran2_st {

    long x, y, v[97];

};

static void

lran2_init(struct lran2_st* d, long seed)

{

    long x;

    int j;

    x = (IC - seed) % LRAN2_MAX;

    if(x < 0) x = -x;

    for(j=0; j<97; j++) {

	x = (IA*x + IC) % LRAN2_MAX;

	d->v[j] = x;

    }

    d->x = (IA*x + IC) % LRAN2_MAX;

    d->y = d->x;

}

#ifdef __GNUC__

__inline__

#endif

static long

lran2(struct lran2_st* d)

{

    int j = (d->y % 97);

    d->y = d->v[j];

    d->x = (IA*d->x + IC) % LRAN2_MAX;

    d->v[j] = d->x;

    return d->y;

}

#undef IA

#undef IC

#endif