/* nag_bessel_j_alpha (s18ekc) Example Program.
 *
 * Copyright 2000 Numerical Algorithms Group.
 *
 * NAG C Library
 *
 * Mark 6, 2000.
 * Mark 8 revised, 2004.
 *
 */

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

int main(void)
{

  Complex *b=0;
  Integer exit_status=0, i, nl;
  NagError fail;
  double a, alpha, d, x;

  INIT_FAIL(fail);
  /* Skip heading in data file */
  Vscanf("%*[^\n]");
  Vprintf("nag_bessel_j_alpha (s18ekc) Example Program Results\n");
  if ( !( b = NAG_ALLOC(101, Complex)) )
    {
      Vprintf("Allocation failure\n");
      exit_status = -1;
      goto END;
    }
  while (scanf("%lf %lf %ld%*[^\n]", &x, &a, &nl) != EOF)
    {
      Vprintf("  x     a      nl\n");
      Vprintf("%4.1f  %4.1f %6ld\n\n", x, a, nl);
      /* nag_bessel_j_alpha (s18ekc).
       * Bessel functions J_(alpha~+~n~-~1)(x) or
       * J_(alpha~-~n~+~1)(x) for real x~!=~0, non-negative
       * alpha~<~1 and n~=~1~,~2~,~...~,~|N|~+~1
       */
      nag_bessel_j_alpha(x, a, nl, b, &fail);
      if (fail.code == NE_NOERROR)
        {
          Vprintf(" Requested values of J_alpha(X)\n\n");
          alpha = a;
          Vprintf("     alpha              J_alpha(X)\n");
          for (i = 1; i <= ABS(nl) + 1; ++i)
            {
              Vprintf(" %12.4e   (%12.4e, %12.4e)\n", alpha, b[i - 1].re,
                      b[i - 1].im);
              d = (double) nl;
              alpha += SIGN(1.0, d);
            }
        }
      else
        {
          Vprintf("Error from nag_bessel_j_alpha (s18ekc).\n%s\n",
                  fail.message);
          exit_status = 1;
          goto END;
        }
    }
 END:
  if (b) NAG_FREE(b);
  return exit_status;
}