branches/dynamic/examples/basic/random_points.cc

   1 // Voronoi calculation example code
   2 //
   3 // Author   : Chris H. Rycroft (LBL / UC Berkeley)
   4 // Email    : chr@alum.mit.edu
   5 // Date     : July 1st 2008
   6
   7 #include "voro++.cc"
   8
   9 // Set up constants for the container geometry
  10 const double x_min=-1,x_max=1;
  11 const double y_min=-1,y_max=1;
  12 const double z_min=-1,z_max=1;
  13 const double cvol=(x_max-x_min)*(y_max-y_min)*(x_max-x_min);
  14
  15 // Set up the number of blocks that the container is divided into
  16 const int n_x=6,n_y=6,n_z=6;
  17
  18 // Set the number of particles that are going to be randomly introduced
  19 const int particles=20;
  20
  21 // This function returns a random double between 0 and 1
  22 double rnd() {return double(rand())/RAND_MAX;}
  23
  24 int main() {
  25         int i;
  26         double x,y,z;
  27
  28         // Create a container with the geometry given above, and make it
  29         // non-periodic in each of the three coordinates. Allocate space for
  30         // eight particles within each computational block
  31         container con(x_min,x_max,y_min,y_max,z_min,z_max,n_x,n_y,n_z,
  32                         false,false,false,8);
  33
  34         // Randomly add particles into the container
  35         for(i=0;i<particles;i++) {
  36                 x=x_min+rnd()*(x_max-x_min);
  37                 y=y_min+rnd()*(y_max-y_min);
  38                 z=z_min+rnd()*(z_max-z_min);
  39                 con.put(i,x,y,z);
  40         }
  41
  42         // Sum up the volumes, and check that this matches the container volume
  43         double vvol=con.sum_cell_volumes();
  44         cout << "Container volume : " << cvol << "\n";
  45         cout << "Voronoi volume   : " << vvol << "\n";
  46         cout << "Difference       : " << vvol-cvol << endl;
  47
  48         // Output the particle positions in gnuplot format
  49         con.draw_particles("random_points_p.gnu");
  50
  51         // Output the Voronoi cells in gnuplot format
  52         con.draw_cells_gnuplot("random_points_v.gnu");
  53 }