// boundary_node_list.edp
//
//  Discussion:
//
//    Produce a list of the nodes along the boundary.
//
//  Location:
//
//    http://people.sc.fsu.edu/~jburkardt/freefem_src/boundary_node_list/boundary_node_list.edp
//
//  Licensing:
//
//    This code is distributed under the MIT license.
//
//  Modified:
//
//    27 July 2015
//
//  Author:
//
//    John Burkardt
//
  cout << "\n";
  cout << "BOUNDARY_NODE_LIST:\n";
  cout << "  FreeFem++ version\n";
  cout << "  For a given mesh, produce a list of indices of nodes\n";
  cout << "  which lie on the boundary.\n";
//
//  Create a mesh of 6x3 elements in [2,8] x [10,13].
//
  mesh Th = square ( 6, 3, [ 6 * x + 2, 3 * y + 10 ] );
//
//  Plot the mesh.
//              
  plot ( Th, wait = false, ps = "boundary_node_list_mesh.ps" );
//
//  Report.
//
  int trianglenum = Th.nt;

  cout << "\n";
  cout << "  Number of triangles = " << trianglenum << "\n";

  for ( int i = 0; i < trianglenum; i++ )
  {
    cout << "\n";
    cout << "  Triangle " << i << "\n";
    for ( int j = 0; j < 3; j++ )
    {
      cout << "  Node " << j << "  (x,y) = ( " << Th[i][j].x << ", " << Th[i][j].y << " )\n"; 
    }
  }
//
//  Boundary elements?
//
  int triangleboundarynum = Th.nbe;

  cout << "  Number of boundary elements = " << triangleboundarynum << "\n";

  for ( int i = 0; i < triangleboundarynum; i++ )
  {
    cout << "\n";
    cout << "  Boundary element " << i << "\n";
    cout << "  Mysterious boundary element index = " << Th.be(i) << "\n";
    cout << "  Vertex 0 = " << Th.be(i)[0] << "\n";
    cout << "  Vertex 1 = " << Th.be(i)[1] << "\n";
    cout << "  Element = " << Th.be(i).Element << "\n";
    cout << "  Element edge = " << Th.be(i).whoinElement << "\n";
  }
//
//  Terminate.
//
  cout << "\n";
  cout << "boundary_node_list:\n";
  cout << "  Normal end of execution.\n";

  exit ( 0 );