NAG Library Manual, Mark 29
Interfaces:  FL   CL   CPP   AD 

NAG CL Interface Introduction
Example description
/* nag_sum_chebyshev (c06dcc) Example Program.
 *
 * Copyright 2023 Numerical Algorithms Group.
 *
 * Mark 29.0, 2023.
 */

#include <nag.h>

int main(void) {
  /* Scalars */
  Integer exit_status = 0, i, lx, n;
  double xmax, xmin;
  /* Arrays */
  char sstr[30];
  double *c = 0, *res = 0, *x = 0;
  /* Nag Types */
  Nag_Series s;
  NagError fail;

  INIT_FAIL(fail);

  printf("nag_sum_chebyshev (c06dcc) Example Program Results\n");
  /* Skip heading in data file */
  scanf("%*[^\n]");
  scanf("%" NAG_IFMT "%*[^\n]%" NAG_IFMT "%*[^\n]", &n, &lx);

  if (!(c = NAG_ALLOC(n, double)) || !(res = NAG_ALLOC(lx, double)) ||
      !(x = NAG_ALLOC(lx, double))) {
    printf("Allocation failure\n");
    exit_status = -1;
    goto END;
  }
  for (i = 0; i < lx; i++)
    scanf("%lf", &x[i]);
  scanf("%*[^\n]");
  scanf("%lf%lf%*[^\n]", &xmin, &xmax);
  scanf("%29s%*[^\n]", sstr);
  /* nag_enum_name_to_value (x04nac).
   * Converts NAG enum member name to value
   */
  s = (Nag_Series)nag_enum_name_to_value(sstr);
  for (i = 0; i < n; i++)
    scanf("%lf", &c[i]);

  /* nag_sum_chebyshev (c06dcc).
   * Evaluates a polynomial from its Chebyshev series representation.
   */
  nag_sum_chebyshev(x, lx, xmin, xmax, c, n, s, res, &fail);
  if (fail.code != NE_NOERROR) {
    printf("Error from nag_sum_chebyshev (c06dcc).\n%s\n", fail.message);
    exit_status = 1;
    goto END;
  }

  printf("\n%8s%16s\n", "x", "sum at x");
  for (i = 0; i < lx; i++)
    printf("%11.4f%13.4f\n", x[i], res[i]);

END:
  NAG_FREE(c);
  NAG_FREE(res);
  NAG_FREE(x);

  return exit_status;
}