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

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

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

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

  INIT_FAIL(fail);

  Vprintf("nag_2d_spline_eval_rect (e02dfc) Example Program Results\n");
  /* Skip heading in data file */
  Vscanf("%*[^\n]");
  /* Read mx and my, the number of grid points in the x and y
   * directions respectively.
   */
  Vscanf("%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)) )
        {
          Vprintf("Allocation failure\n");
          exit_status = -1;
          goto END;
        }
    }
  else
    {
      Vprintf("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.
   */
  Vscanf("%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)) )
    {
      Vprintf("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++)
    Vscanf("%lf",&(spline.lamda[i]));
  for (i=0; i<spline.ny;  i++)
    Vscanf("%lf",&(spline.mu[i]));
  /* Read spline.c, the bicubic spline coefficients. */
  for (i=0; i<(spline.nx-4)*(spline.ny-4); i++)
    Vscanf("%lf",&(spline.c[i]));
  /* Read the x and y co-ordinates defining the evaluation grid. */
  for (i=0; i<mx;  i++)
    Vscanf("%lf",&x[i]);
  for (i=0; i<my;  i++)
    Vscanf("%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)
    {
      Vprintf("Error from nag_2d_spline_eval_rect (e02dfc).\n%s\n",
              fail.message);
      exit_status = 1;
      goto END;
    }

  /* Print the result array. */
  Vprintf("Spline evaluated on x-y grid (x across, y down):\n      ");
  for (i=0; i<mx;  i++)
    Vprintf("%2.1f      ",x[i]);
  Vprintf("\n");
  for (j=0; j<my; j++)
    {
      Vprintf("%2.1f",y[j]);
      for (i=0; i<mx; i++)
        Vprintf("%8.3f%s",FF(i,j), (i%7==6 || i==mx-1) ? "\n" : " ");
    }
 END:
  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;
}