On Sun, 22 Jan 2012, David Doria wrote:

...

You would need to do that by hand; note that there is a function to convert from coordinates to graph vertices.

-- Jeremiah Willcock

Hi Jeremiah,

You mean there is something more "built in" than this: ?

#include "boost/graph/adjacency_list.hpp" #include "boost/graph/simple_point.hpp"

namespace boost {   enum vertex_coordinate_t { vertex_coordinate };   BOOST_INSTALL_PROPERTY(vertex, coordinate); };

int main(int argc, char *argv[]) {   typedef boost::simple_point<float> PointType;

  typedef boost::adjacency_list<boost::vecS,                                 boost::vecS,                                 boost::undirectedS,                                 boost::property< boost::vertex_coordinate_t, PointType >                                 > Graph;   Graph g;

  typedef typename boost::property_map<Graph, boost::vertex_coordinate_t>::type CoordinatePropertyMap;   CoordinatePropertyMap coordinatePropertyMap = get(boost::vertex_coordinate, g);

  return 0; }

(i.e. can you point me to the function you are talking about : ) ?)

You can just make a boost::array with the coordinates and call that a vertex descriptor; that equivalence is used often enough that it probably needs to stay stable.

Also, the reason I am not using boost::grid_graph is that there are "holes" in my graph - i.e. not every integer coordinate has a vertex. Does the coordinate-to-vertex_descriptor function you are talking about handle the case when a vertex doesn't exist at the specified coordinate?

If you use a filtered_graph on top of the grid_graph, the trick I mentioned above will work, but you'd want to check the filter condition on the coordinates before using them in the filtered_graph. -- Jeremiah Willcock