/* nag_2d_spline_eval_rect (e02dfc) Example Program.
 *
 * Copyright 1991 Numerical Algorithms Group.
 *
 * Mark 2, 1991.
 * Mark 8 revised, 2004.
 */

#include <nag.h>
#include <nagx04.h>
#include <stdio.h>
#include <nag_stdlib.h>
#include <nage02.h>

#define FF(I, J) ff[my*(I)+(J)]

int main(int argc, char *argv[])
{
  FILE         *fpin, *fpout;
  Integer      exit_status = 0, i, j, mx, my;
  NagError     fail;
  Nag_2dSpline spline;
  double       *ff = 0, *x = 0, *y = 0;

  INIT_FAIL(fail);

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

  /* 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_2d_spline_eval_rect (e02dfc) Example Program Results\n");
  /* Skip heading in data file */
  fscanf(fpin, "%*[^\n]");
  /* Read mx and my, the number of grid points in the x and y
   * directions respectively.
   */
  fscanf(fpin, "%ld%ld", &mx, &my);
  if (mx >= 1 && my >= 1)
    {
      if (!(x = NAG_ALLOC(mx, double)) ||
          !(y = NAG_ALLOC(my, double)) ||
          !(ff = NAG_ALLOC(mx*my, double)))
        {
          fprintf(fpout, "Allocation failure\n");
          exit_status = -1;
          goto END;
        }
    }
  else
    {
      fprintf(fpout, "Invalid mx or my.\n");
      exit_status = 1;
      return exit_status;
    }
  /* Read spline.nx and spline.ny, the number of knots
   * in the x and y directions.
   */
  fscanf(fpin, "%ld%ld", &(spline.nx), &(spline.ny));
  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)))
    {
      fprintf(fpout, "Storage allocation failed.\n");
      exit_status = -1;
      goto END;
    }
  /* Read the knots spline.lamda[0]...spline.lamda[nx-1]
   * and spline.mu[0]...spline.mu[ny-1].
   */
  for (i = 0; i < spline.nx;  i++)
    fscanf(fpin, "%lf", &(spline.lamda[i]));
  for (i = 0; i < spline.ny;  i++)
    fscanf(fpin, "%lf", &(spline.mu[i]));
  /* Read spline.c, the bicubic spline coefficients. */
  for (i = 0; i < (spline.nx-4)*(spline.ny-4); i++)
    fscanf(fpin, "%lf", &(spline.c[i]));
  /* Read the x and y co-ordinates defining the evaluation grid. */
  for (i = 0; i < mx;  i++)
    fscanf(fpin, "%lf", &x[i]);
  for (i = 0; i < my;  i++)
    fscanf(fpin, "%lf", &y[i]);
  /* Evaluate the spline at the mx by my points. */
  /* nag_2d_spline_eval_rect (e02dfc).
   * Evaluation of bicubic spline, at a mesh of points
   */
  nag_2d_spline_eval_rect(mx, my, x, y, ff, &spline, &fail);
  if (fail.code != NE_NOERROR)
    {
      fprintf(fpout, "Error from nag_2d_spline_eval_rect (e02dfc).\n%s\n",
              fail.message);
      exit_status = 1;
      goto END;
    }

  /* Print the result array. */
  fprintf(fpout, "Spline evaluated on x-y grid (x across, y down):\n      ");
  for (i = 0; i < mx;  i++)
    fprintf(fpout, "%2.1f      ", x[i]);
  fprintf(fpout, "\n");
  for (j = 0; j < my; j++)
    {
      fprintf(fpout, "%2.1f", y[j]);
      for (i = 0; i < mx; i++)
        fprintf(fpout, "%8.3f%s", FF(i, j), (i%7 == 6 || i == mx-1)?"\n":" ");
    }
 END:
  if (fpin != stdin) fclose(fpin);
  if (fpout != stdout) fclose(fpout);
  NAG_FREE(spline.c);
  NAG_FREE(spline.lamda);
  NAG_FREE(spline.mu);
  if (x) NAG_FREE(x);
  if (y) NAG_FREE(y);
  if (ff) NAG_FREE(ff);
  return exit_status;
}