#include <stdlib.h>
#include <math.h>
#include "geostat.h"


/* GENERATION OF A GAUSSIAN WHITE NOISE VECTOR    */
/*input:                                          */
/* seed: seed                                     */
/* n: number of components in the vector          */
/*output:                                         */ 
/* realization: structure defining the realization*/

void generate(long *seed, int n, struct realization_mod *realization)
{
  int i;
  long idum2 = 123456789,iy = 0;
  long *iv;
  int iset =0;

  iv = (long *) malloc(NTAB * sizeof(long));

  /*negative seed*/ 
  if (*seed > 0.0)  
    *seed = -(*seed);

  /*realization definition*/
  (*realization).n = n;
  (*realization).code = 0;
  (*realization).vector = (double *) malloc(n * sizeof(double));
  if ((*realization).vector == NULL) {
     printf("No memory available in generate");
     exit;
  }

  /*Gaussian white noise generation*/
  for (i=0; i < n; i++) 
    (*realization).vector[i] = gasdev(seed,&idum2,&iy,iv,&iset);

  return;
}