/* nag_bessel_k_alpha_scaled (s18ehc) Example Program.
 *
 * Copyright 2024 Numerical Algorithms Group.
 *
 * NAG C Library
 *
 * Mark 30.1, 2024.
 */

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

int main(void) {
  Integer exit_status = 0, i, ia, ja, nl;
  NagError fail;
  double alpha, *b = 0, x;

  INIT_FAIL(fail);

  /* Skip heading in data file */
  scanf("%*[^\n]");
  printf("nag_bessel_k_alpha_scaled (s18ehc) Example Program Results\n");
  if (!(b = NAG_ALLOC(101, double))) {
    printf("Allocation failure\n");
    exit_status = -1;
    goto END;
  }
  while (scanf("%lf %" NAG_IFMT " %" NAG_IFMT " %" NAG_IFMT "%*[^\n]", &x, &ia,
               &ja, &nl) != EOF) {
    printf("  x     ia    ja    nl\n");
    printf("%4.1f%6" NAG_IFMT "%6" NAG_IFMT "%6" NAG_IFMT "\n\n", x, ia, ja,
           nl);
    /* nag_bessel_k_alpha_scaled (s18ehc).
     * Scaled modified Bessel functions K_(alpha+n)(x) for
     * real x > 0, selected values of alpha >= 0 and
     * n = 0,1,...,N
     */
    nag_bessel_k_alpha_scaled(x, ia, ja, nl, b, &fail);
    if (fail.code != NE_NOERROR) {
      printf("Error from nag_bessel_k_alpha_scaled (s18ehc).\n%s\n",
             fail.message);
      exit_status = 1;
      goto END;
    }
    printf(" Requested values of exp(x)*K_alpha(x)\n\n");
    alpha = (double)ia / (double)ja;
    printf("     alpha         exp(x)*K_alpha(x)\n");
    for (i = 0; i <= nl; ++i) {
      printf(" %13.4e      %13.4e\n", alpha, b[i]);
      alpha += 1.0;
    }
  }
END:
  NAG_FREE(b);
  return exit_status;
}