/* nag_fit_dim1_cheb_eval2 (e02akc) Example Program.
 *
 * Copyright 2023 Numerical Algorithms Group.
 *
 * Mark 29.2, 2023.
 */

#include <nag.h>
#include <stdio.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 p, x;
  Integer exit_status, i, m, n, one;
  NagError fail;

  INIT_FAIL(fail);

  exit_status = 0;
  printf("nag_fit_dim1_cheb_eval2 (e02akc) Example Program Results\n");

  n = 6;
  one = 1;

  printf("\n");
  printf("   i   Argument  Value of polynomial\n");

  m = 4;
  for (i = 1; i <= m; ++i) {
    x = (xmin * (double)(m - i) + xmax * (double)(i - 1)) / (double)(m - 1);
    /* nag_fit_dim1_cheb_eval2 (e02akc).
     * Evaluation of fitted polynomial in one variable from
     * Chebyshev series form
     */
    nag_fit_dim1_cheb_eval2(n, xmin, xmax, a, one, x, &p, &fail);
    if (fail.code != NE_NOERROR) {
      printf("Error from nag_fit_dim1_cheb_eval2 (e02akc).\n%s\n",
             fail.message);
      exit_status = 1;
      goto END;
    }
    printf("%4" NAG_IFMT "%10.4f    %9.4f\n", i, x, p);
  }

END:
  return exit_status;
}