/* nag_1d_cheb_intg (e02ajc) Example Program.
 *
 * Copyright 2014 Numerical Algorithms Group.
 *
 * Mark 7, 2001.
 */

#include <stdio.h>
#include <nag.h>
#include <nag_stdlib.h>
#include <nage02.h>

int main(void)
{
  /* Initialized data */
  const double xmin = -0.5;
  const double xmax = 2.5;
  const double a[7] =
  { 2.53213, 1.13032, 0.2715, 0.04434, 0.00547, 5.4e-4, 4e-5 };

  /* Scalars */
  double       ra, rb, result, xa, xb, zero;
  Integer      exit_status, n, one;
  NagError     fail;

  /* Arrays */
  double       *aint = 0;

  INIT_FAIL(fail);

  exit_status = 0;
  printf("nag_1d_cheb_intg (e02ajc) Example Program Results\n");

  n = 6;
  zero = 0.0;
  one = 1;

  /* Allocate memory */
  if (!(aint = NAG_ALLOC(n + 2, double)))
    {
      printf("Allocation failure\n");
      exit_status = -1;
      goto END;
    }

  /* nag_1d_cheb_intg (e02ajc).
   * Integral of fitted polynomial in Chebyshev series form
   */
  nag_1d_cheb_intg(n, xmin, xmax, a, one, zero, aint, one, &fail);
  if (fail.code != NE_NOERROR)
    {
      printf("Error from nag_1d_cheb_intg (e02ajc).\n%s\n",
              fail.message);
      exit_status = 1;
      goto END;
    }

  xa = 0.0;
  xb = 2.0;
  /* nag_1d_cheb_eval2 (e02akc).
   * Evaluation of fitted polynomial in one variable from
   * Chebyshev series form
   */
  nag_1d_cheb_eval2(n+1, xmin, xmax, aint, one, xa, &ra, &fail);
  if (fail.code != NE_NOERROR)
    {
      printf("Error from nag_1d_cheb_eval2 (e02akc).\n%s\n",
              fail.message);
      exit_status = 1;
      goto END;
    }

  /* nag_1d_cheb_eval2 (e02akc), see above. */
  nag_1d_cheb_eval2(n+1, xmin, xmax, aint, one, xb, &rb, &fail);
  if (fail.code != NE_NOERROR)
    {
      printf("Error from nag_1d_cheb_eval2 (e02akc).\n%s\n",
              fail.message);
      exit_status = 1;
      goto END;
    }

  result = rb - ra;
  printf("\n");
  printf("Value of definite integral is %10.4f\n", result);
 END:
  NAG_FREE(aint);

  return exit_status;
}