/* nag_fit_dim2_spline_evalv (e02dec) Example Program.
 *
 * Copyright 2024 Numerical Algorithms Group.
 *
 * Mark 30.1, 2024.
 */

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

int main(void) {
  Integer exit_status = 0, i, m;
  NagError fail;
  Nag_2dSpline spline;
  double *ff = 0, *x = 0, *y = 0;

  INIT_FAIL(fail);

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

  printf("nag_fit_dim2_spline_evalv (e02dec) Example Program Results\n");
  scanf("%*[^\n]"); /* Skip heading in data file */
  /* Read m, the number of spline evaluation points. */
  scanf("%" NAG_IFMT "", &m);
  if (m >= 1) {
    if (!(x = NAG_ALLOC(m, double)) || !(y = NAG_ALLOC(m, double)) ||
        !(ff = NAG_ALLOC(m, double))) {
      printf("Allocation failure\n");
      exit_status = -1;
      goto END;
    }
  } else {
    printf("Invalid m.\n");
    exit_status = 1;
    return exit_status;
  }
  /* Read nx and ny, the number of knots in the x and y directions. */
  scanf("%" NAG_IFMT "%" NAG_IFMT "", &(spline.nx), &(spline.ny));
  if (spline.nx >= 8 && spline.ny >= 8) {
    if (!(spline.c = NAG_ALLOC((spline.nx - 4) * (spline.ny - 4), double)) ||
        !(spline.lamda = NAG_ALLOC(spline.nx, double)) ||
        !(spline.mu = NAG_ALLOC(spline.ny, double))) {
      printf("Allocation failure\n");
      exit_status = -1;
      goto END;
    }
  } else {
    printf("Invalid spline.nx or spline.ny.\n");
    exit_status = 1;
    return exit_status;
  }

  /* read the knots lamda[0] .. lamda[nx-1] and mu[0] .. mu[ny-1]. */
  for (i = 0; i < spline.nx; i++)
    scanf("%lf", &(spline.lamda[i]));
  for (i = 0; i < spline.ny; i++)
    scanf("%lf", &(spline.mu[i]));
  /* Read c, the bicubic spline coefficients. */
  for (i = 0; i < (spline.nx - 4) * (spline.ny - 4);
       scanf("%lf", &(spline.c[i])), i++)
    ;
  /* Read the x and y co-ordinates of the evaluation points. */
  for (i = 0; i < m; i++)
    scanf("%lf%lf", &x[i], &y[i]);
  /* Evaluate the spline at the m points. */
  /* nag_fit_dim2_spline_evalv (e02dec).
   * Evaluation of bicubic spline, at a set of points
   */
  nag_fit_dim2_spline_evalv(m, x, y, ff, &spline, &fail);
  if (fail.code != NE_NOERROR) {
    printf("Error from nag_fit_dim2_spline_evalv (e02dec).\n%s\n",
           fail.message);
    exit_status = 1;
    goto END;
  }

  /* Print the results. */
  printf("      i          x[i]       y[i]       ff[i]\n");
  for (i = 0; i < m; i++)
    printf("%7" NAG_IFMT "    %11.3f%11.3f%11.3f\n", i, x[i], y[i], ff[i]);
  NAG_FREE(spline.lamda);
  NAG_FREE(spline.mu);
  NAG_FREE(spline.c);
END:
  NAG_FREE(x);
  NAG_FREE(y);
  NAG_FREE(ff);
  return exit_status;
}