branches/dynamic/examples/walls/frustum.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 const double pi=3.1415926535897932384626433832795;
  10
  11 int main() {
  12         int i=0;
  13         fpoint x,y,z,evol,vvol;
  14
  15         // Create a container with the geometry given above, and make it
  16         // non-periodic in each of the three coordinates. Allocate space for
  17         // eight particles within each computational block.
  18         container con(-1.2,1.2,-1.2,1.2,0,1,14,14,7,
  19                         false,false,false,8);
  20
  21         // Add a cylindrical wall to the container
  22         wall_cone cone(0,0,2,0,0,-1,atan(0.5));
  23         con.add_wall(cone);
  24
  25         // Place particles in a regular grid within the frustum, for points
  26         // which are within the wall boundaries
  27         for(z=0.1;z<1;z+=0.2) for(y=-0.95;y<1;y+=0.2) for(x=-0.95;x<1;x+=0.2) {
  28                 if (con.point_inside(x,y,z)) {
  29                         con.put(i,x,y,z);i++;
  30                 }
  31         }
  32
  33         // Output the particle positions and Voronoi cells in Gnuplot format
  34         con.draw_particles("frustum_p.gnu");
  35         con.draw_cells_gnuplot("frustum_v.gnu");
  36
  37         // Output the particle positions and Voronoi cells in POV-Ray format
  38         con.draw_particles_pov("frustum_p.pov");
  39         con.draw_cells_pov("frustum_v.pov");
  40
  41         // Compute the volume of the Voronoi cells and compare it to the
  42         // exact frustum volume
  43         evol=pi*1*(0.5*0.5+0.5*1+1*1)/3;
  44         vvol=con.sum_cell_volumes();
  45         cout << "Exact frustum volume : " << evol << "\n";
  46         cout << "Voronoi cell volume  : " << vvol << "\n";
  47         cout << "Difference           : " << vvol-evol << endl;
  48 }