/*
	irl_utility.c
*/


#include <stdio.h>
#include <stdlib.h> 
#include <math.h>

/* a random sample from standard normal distribution */
double nrand()
{
    static int sw = 0;
    static double r1, r2, s;

    if (sw == 0) {
        sw = 1;
        do {
            r1 = 2.0 * drand48() - 1.0;
            r2 = 2.0 * drand48() - 1.0;
            s = r1 * r1 + r2 * r2;
        } while (s > 1.0 || s == 0.0);
        s = sqrt(-2.0 * log(s) / s);
        return (r1 * s);
    } else {
        sw = 0;
        return (r2 * s);
    }
}



/*** Allocate 1d array of unsinged long long int ***/

unsigned long long int *alloc_1d_ullint(int n){

  unsigned long long int   *new;

  new = (unsigned long long int *) malloc ((unsigned) (n * sizeof (unsigned long long)));
  if (new == NULL) {
    printf("ALLOC_1D_LLU: Couldn't allocate array of unsigned long long\n");
    return (NULL);
  }
  return (new);
}


/*** Allocate 1d array of chars ***/

unsigned char *alloc_1d_uchar(int n){

  unsigned char *new;

  new = (unsigned char *) malloc ((unsigned) (n * sizeof (unsigned char)));
  if (new == NULL) {
    printf("ALLOC_1D_UCHAR: Couldn't allocate array of uchars\n");
    return (NULL);
  }
  return (new);
}


/*** Allocate 2d array of char`s ***/
unsigned char **alloc_2d_uchar(int m, int n){

  int i;
  unsigned char **new;

  new = (unsigned char **) malloc ((unsigned) (m * sizeof (unsigned char *)));
  if (new == NULL) {
    printf("ALLOC_2D_CHAR: Couldn't allocate array of uchar ptrs\n");
    return (NULL);
  }

  for (i = 0; i < m; i++) {
    new[i] = alloc_1d_uchar(n);
  }
  return (new);
}


/*** Allocate 1d array of ints ***/
int *alloc_1d_int(int n){

  int *new;

  new = (int *) malloc ((unsigned) (n * sizeof (int)));
  if (new == NULL) {
    printf("ALLOC_1D_INT: Couldn't allocate array of ints\n");
    return (NULL);
  }
  return (new);
}

/*** Allocate 2d array of int`s ***/
int **alloc_2d_int(int m, int n){

  int i;
  int **new;

  new = (int **) malloc ((unsigned) (m * sizeof (int *)));
  if (new == NULL) {
    printf("ALLOC_2D_INT: Couldn't allocate array of int ptrs\n");
    return (NULL);
  }

  for (i = 0; i < m; i++) {
    new[i] = alloc_1d_int(n);
  }
  return (new);
}




/*** Allocate 1d array of doubles ***/

double *alloc_1d_dbl(int n){

  double *new;

  new = (double *) malloc ((unsigned) (n * sizeof (double)));
  if (new == NULL) {
    printf("ALLOC_1D_DBL: Couldn't allocate array of doubles\n");
    return (NULL);
  }
  return (new);
}


/*** Allocate 2d array of doubles ***/

double **alloc_2d_dbl(int m, int n){

  int i;
  double **new;

  new = (double **) malloc ((unsigned) (m * sizeof (double *)));
  if (new == NULL) {
    printf("ALLOC_2D_DBL: Couldn't allocate array of dbl ptrs\n");
    return (NULL);
  }

  for (i = 0; i < m; i++) {
    new[i] = alloc_1d_dbl(n);
  }

  return (new);
}