/* nag_1d_ratnl_eval (e01rbc) Example Program.
 *
 * Copyright 2001 Numerical Algorithms Group.
 *
 * Mark 7, 2001.
 */

#include <stdio.h>
#include <nag.h>
#include <nagx04.h>
#include <nag_stdlib.h>
#include <nage01.h>

int main(int argc, char *argv[])
{
  FILE     *fpin, *fpout;
  /* Scalars */
  double   f, x;
  Integer  exit_status, i, m;
  NagError fail;

  /* Arrays */
  double   *a = 0, *u = 0;

  exit_status = 0;

  INIT_FAIL(fail);

  /* Check for command-line IO options */
  fpin = nag_example_file_io(argc, argv, "-data", NULL);
  fpout = nag_example_file_io(argc, argv, "-results", NULL);
  fprintf(fpout, "nag_1d_ratnl_eval (e01rbc) Example Program Results\n");

  /* Skip heading in data file */
  fscanf(fpin, "%*[^\n] ");
  m = 4;

  /* Allocate memory */
  if (!(a = NAG_ALLOC(m, double)) ||
      !(u = NAG_ALLOC(m, double)))
    {
      fprintf(fpout, "Allocation failure\n");
      exit_status = -1;
      goto END;
    }

  for (i = 1; i <= m; ++i)
    fscanf(fpin, "%lf", &a[i-1]);
  fscanf(fpin, "%*[^\n] ");

  for (i = 1; i <= m - 1; ++i)
    fscanf(fpin, "%lf", &u[i-1]);
  fscanf(fpin, "%*[^\n] ");

  fscanf(fpin, "%lf%*[^\n] ", &x);

  fprintf(fpout, "\n");
  fprintf(fpout, "x = %13.4e\n", x);

  /* nag_1d_ratnl_eval (e01rbc).
   * Interpolated values, evaluate rational interpolant
   * computed by nag_1d_ratnl_interp (e01rac), one variable
   */
  nag_1d_ratnl_eval(m, a, u, x, &f, &fail);
  if (fail.code == NE_NOERROR)
    {
      fprintf(fpout, "\n");
      fprintf(fpout, "The value of R(x) is %13.4e\n", f);
    }
  else
    {
      fprintf(fpout, "Error from nag_1d_ratnl_eval (e01rbc).\n%s\n",
              fail.message);
      exit_status = 1;
    }
 END:
  if (fpin != stdin) fclose(fpin);
  if (fpout != stdout) fclose(fpout);
  if (a) NAG_FREE(a);
  if (u) NAG_FREE(u);

  return exit_status;
}