/***************************************************************/
void d_swap(double *a, double *b)
{
register double tmp;
tmp = *a; *a = *b; *b = tmp;
}

void i_swap(int *a, int *b)
{
register int tmp;
tmp = *a; *a = *b; *b = tmp;
}
/***************************************************************/

/***************************************************************/
void my_sort(int l, int r, double *arr, int *ind)
{

int    i, j, cikl;
double tmp;

i = l; j = r;
tmp = arr[(l+r)/2];

cikl = 1;

while (cikl)
  {
    while (arr[i]<tmp) i++;
    while (tmp<arr[j]) j--;

    if (i<=j)
     {
	d_swap(&arr[i],&arr[j]);
	i_swap(&ind[i],&ind[j]);
	i++; j--;
     }
    else
     {
	cikl = 0;
     }

  }

  if (l<j) my_sort(l, j, arr, ind);
  if (i<r) my_sort(i, r, arr, ind);
}
/***************************************************************/

/***************************************************************/
double my_select(int n_1, int n_2, int k, double *arr, int *ind)
{

int   i, ir, j, l, mid, a_ind;
double a;

l  = n_1;
ir = n_2;

for(;;)
  {

  if (ir <= l+1) 
    {

    if (ir == l+1 && arr[ir] < arr[l]) 
      {
      d_swap(&arr[l],&arr[ir]);
      i_swap(&ind[l],&ind[ir]);
      }

    return(arr[k]);

    } 
    else 
    {

    mid=(l+ir) >> 1;

    d_swap(&arr[mid],&arr[l+1]);
    i_swap(&ind[mid],&ind[l+1]);

    if (arr[l+1] > arr[ir]) 
      {
      d_swap(&arr[l+1],&arr[ir]);
      i_swap(&ind[l+1],&ind[ir]);
      }

    if (arr[l] > arr[ir]) 
      {
      d_swap(&arr[l],&arr[ir]);
      i_swap(&ind[l],&ind[ir]);
      }

    if (arr[l+1] > arr[l])
      {
      d_swap(&arr[l+1],&arr[l]);
      i_swap(&ind[l+1],&ind[l]);
      }

    i = l+1;
    j = ir;
    a = arr[l];
    a_ind = ind[l];

    for (;;) 
     {
     do i++; while (arr[i] < a);
     do j--; while (arr[j] > a);
     if (j < i) break;
     d_swap(&arr[i],&arr[j]);
     i_swap(&ind[i],&ind[j]);
     }

    arr[l] = arr[j];
    ind[l] = ind[j];
    arr[j] = a;
    ind[j] = a_ind;
    if (j >= k) ir = j-1;
    if (j <= k) l = i;

    }
  }
}
/***************************************************************/

/***************************************************************/
/*
double lagrange_radius(double percent)
{ 
int    Nb;
double tmp;

Nb = (int)(percent * N);

my_sort(0, N-1, d, ind);

tmp = my_select(0, N-1, Nb-1, d, ind); d[Nb-1] = tmp;

return(tmp);
}
*/
/***************************************************************/