/* nag_interp_dim1_ratnl (e01rac) Example Program.
 *
 * Copyright 2024 Numerical Algorithms Group.
 *
 * Mark 30.1, 2024.
 */

#include <nag.h>
#include <stdio.h>

int main(void) {

  /* Scalars */
  Integer exit_status, i, m, n;
  NagError fail;

  /* Arrays */
  double *a = 0, *f = 0, *u = 0, *x = 0;

  exit_status = 0;
  INIT_FAIL(fail);

  printf("nag_interp_dim1_ratnl (e01rac) Example Program Results\n");

  /* Skip heading in data file */
  scanf("%*[^\n] ");
  n = 5;

  /* Allocate memory */
  if (!(a = NAG_ALLOC(n, double)) || !(f = NAG_ALLOC(n, double)) ||
      !(u = NAG_ALLOC(n, double)) || !(x = NAG_ALLOC(n, double))) {
    printf("Allocation failure\n");
    exit_status = -1;
    goto END;
  }

  for (i = 1; i <= n; ++i)
    scanf("%lf", &x[i - 1]);
  scanf("%*[^\n] ");

  for (i = 1; i <= n; ++i)
    scanf("%lf", &f[i - 1]);
  scanf("%*[^\n] ");

  /* nag_interp_dim1_ratnl (e01rac).
   * Interpolating functions, rational interpolant, one
   * variable
   */
  nag_interp_dim1_ratnl(n, x, f, &m, a, u, &fail);
  if (fail.code != NE_NOERROR) {
    exit_status = 1;
    printf("Error from nag_interp_dim1_ratnl (e01rac).\n%s\n", fail.message);
    goto END;
  }

  printf("\n");
  printf("The values of u[j] are\n");
  for (i = 1; i <= m - 1; ++i) {
    printf("%13.4e", u[i - 1]);
    printf(i % 4 == 0 || i == m - 1 ? "\n" : " ");
  }
  printf("\n");

  printf("The Thiele coefficients a[j] are\n");
  for (i = 1; i <= m; ++i) {
    printf("%13.4e", a[i - 1]);
    printf(i % 4 == 0 || i == m ? "\n" : " ");
  }

END:
  NAG_FREE(a);
  NAG_FREE(f);
  NAG_FREE(u);
  NAG_FREE(x);

  return exit_status;
}