/* nag_fit_dim1_spline_eval (e02bbc) Example Program.
 *
 * Copyright 2021 Numerical Algorithms Group.
 *
 * Mark 27.3, 2021.
 *
 */

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

int main(void) {
  Integer exit_status = 0, j, m, ncap, ncap7, r;
  Nag_Spline spline;
  double a, b, s, x;
  NagError fail;

  INIT_FAIL(fail);

  /* Initialize spline */
  spline.lamda = 0;
  spline.c = 0;

  printf("nag_fit_dim1_spline_eval (e02bbc) Example Program Results\n");
  scanf("%*[^\n]"); /* Skip heading in data file */
  while (scanf("%" NAG_IFMT "", &m) != EOF)
  {
    if (m <= 0) {
      printf("Invalid m.\n");
      exit_status = 1;
      return exit_status;
    }
    scanf("%" NAG_IFMT "", &ncap);
    ncap7 = ncap + 7;
    if (ncap > 0) {
      spline.n = ncap7;
      if (!(spline.c = NAG_ALLOC(ncap7, double)) ||
          !(spline.lamda = NAG_ALLOC(ncap7, double))) {
        printf("Allocation failure\n");
        exit_status = -1;
        goto END;
      }
    } else {
      printf("Invalid ncap.\n");
      exit_status = 1;
      return exit_status;
    }
    for (j = 0; j < ncap7; j++)
      scanf("%lf", &(spline.lamda[j]));
    for (j = 0; j < ncap + 3; j++)
      scanf("%lf", &(spline.c[j]));
    a = spline.lamda[3];
    b = spline.lamda[ncap + 3];
    printf("Augmented set of knots stored in spline.lamda:\n");
    for (j = 0; j < ncap7; j++)
      printf("%10.4f%s", spline.lamda[j],
             (j % 6 == 5 || j == ncap7 - 1) ? "\n" : " ");
    printf("\nB-spline coefficients stored in spline.c\n\n");
    for (j = 0; j < ncap + 3; j++)
      printf("%10.4f%s", spline.c[j],
             (j % 6 == 5 || j == ncap + 2) ? "\n" : " ");
    printf("\n      x         Value of cubic spline\n\n");
    for (r = 1; r <= m; ++r) {
      x = ((double)(m - r) * a + (double)(r - 1) * b) / (double)(m - 1);
      /* nag_fit_dim1_spline_eval (e02bbc).
       * Evaluation of fitted cubic spline, function only
       */
      nag_fit_dim1_spline_eval(x, &s, &spline, &fail);
      if (fail.code != NE_NOERROR) {
        printf("Error from nag_fit_dim1_spline_eval (e02bbc).\n%s\n",
               fail.message);
        exit_status = 1;
        goto END;
      }
      printf("%10.4f%15.4f\n", x, s);
    }
    NAG_FREE(spline.c);
    NAG_FREE(spline.lamda);
  }
END:
  return exit_status;
}