#include <stdlib.h>
#include "geostat.h"


/*computes the size of the grid for FFTs*/
/*input:                                           */
/*variogram: structure defining the variogram model*/
/*grid: structure defining the actual grid         */
/*output:                                          */
/*n: vector with the number of cells along the     */
/*   X, Y and Z axes for the underlying grid       */
/*   i = [0 1 2]                                   */
void cgrid(struct vario_mod variogram, struct grid_mod grid, int n[3])
{
  int i,N;
  double D;
  
  if (n == NULL || n[0] == 0 || n[1] == 0 || n[2] == 0) {
    for (i = 0; i<3; i++) {
      switch (i) {
      case 0: 
	N = grid.NX;
	D = grid.DX;
	break;
      case 1:
	N = grid.NY;
	D = grid.DY;
	break;
      case 2:
	N = grid.NZ;
	D = grid.DZ;
	break;
      }
      n[i] = length(N,i,variogram.scf,variogram.ap,D,variogram.Nvario);
    }
  } else {
    if ((n[0]<grid.NX) || (n[1]<grid.NY) || (n[2]<grid.NZ)) {
      printf("Indicated dimensions are inappropriate in cgrid");
      exit;
    }
  }
  return;
}