/* nag_1d_cheb_deriv (e02ahc) Example Program.
 *
 * Copyright 2001 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       deriv, deriv2, patm1, x;
  Integer      exit_status, i, m, n, one;
  NagError     fail;

  /* Arrays */
  double       *adif = 0, *adif2 = 0;

  INIT_FAIL(fail);

  exit_status = 0;
  printf("nag_1d_cheb_deriv (e02ahc) Example Program Results\n");

  n = 6;
  one = 1;

  /* Allocate memory */
  if (!(adif = NAG_ALLOC(n + 1, double)) ||
      !(adif2 = NAG_ALLOC(n + 1, double)))
    {
      printf("Allocation failure\n");
      exit_status = -1;
      goto END;
    }

  /* nag_1d_cheb_deriv (e02ahc).
   * Derivative of fitted polynomial in Chebyshev series form
   */
  nag_1d_cheb_deriv(n, xmin, xmax, a, one, &patm1, adif, one, &fail);
  if (fail.code != NE_NOERROR)
    {
      printf("Error from nag_1d_cheb_deriv (e02ahc) call 1.\n%s\n",
              fail.message);
      exit_status = 1;
      goto END;
    }

  /* nag_1d_cheb_deriv (e02ahc), see above. */
  nag_1d_cheb_deriv(n, xmin, xmax, adif, one, &patm1, adif2, one, &fail);
  if (fail.code != NE_NOERROR)
    {
      printf("Error from nag_1d_cheb_deriv (e02ahc) call 2.\n%s\n",
              fail.message);
      exit_status = 1;
      goto END;
    }

  m = 4;
  printf("\n");
  printf("   i  Argument    1st deriv    2nd deriv\n");

  for (i = 1; i <= m; ++i)
    {
      x = (xmin * (double)(m - i) + xmax * (double)(i - 1)) / (double)(m - 1);
      /* nag_1d_cheb_eval2 (e02akc).
       * Evaluation of fitted polynomial in one variable from
       * Chebyshev series form
       */
      nag_1d_cheb_eval2(n, xmin, xmax, adif, one, x, &deriv, &fail);
      if (fail.code != NE_NOERROR)
        {
          printf("Error from nag_1d_cheb_eval2 (e02akc) call 1.\n%s\n",
                  fail.message);
          exit_status = 1;
          goto END;
        }
      /* nag_1d_cheb_eval2 (e02akc), see above. */
      nag_1d_cheb_eval2(n, xmin, xmax, adif2, one, x, &deriv2, &fail);
      if (fail.code != NE_NOERROR)
        {
          printf("Error from nag_1d_cheb_eval2 (e02akc) call 2.\n%s\n",
                  fail.message);
          exit_status = 1;
          goto END;
        }
      printf("%4ld%9.4f    %9.4f    %9.4f    \n", i, x, deriv, deriv2);
    }

 END:
  if (adif) NAG_FREE(adif);
  if (adif2) NAG_FREE(adif2);

  return exit_status;
}