void examine_edge(Edge e, Graph& g) {
invoke_visitors(m_vis, e, g, on_examine_edge());
}
void evaluateGeodesicDist(GridSpecs grid_specs, std::vector<Polygon_2> polygons,
std::vector<Point> ref_points, IOSpecs io_specs)
{
// -- grid definition --
// no. of rows and columns
int no_rows, no_cols;
no_rows = (int)grid_specs.getGridSpecs().at(0);
no_cols = (int)grid_specs.getGridSpecs().at(1);
// grid points
int no_gpoints;
no_gpoints = (no_rows*no_cols);
// spatial locations of the grid points
std::vector<Point_2> grid_points;
// evaluating the spatial locations of the grid points
initGrid(grid_specs, grid_points);
//--
// -- graph definition --
//
// note that two different graphs need to be considered:
//
// 1) effective graph -
// graph associated with the complementary domain;
// the nodes of this graph do not include the grid points
// associated with the polygon(s);
//
// 2) BGL graph -
// graph processed by the BGL library;
// this graph coincides with the grid;
// the nodes of this graph coincide the grid points;
// the nodes associated with the polygon(s) are nodes
// with no edges, i.e. they are nodes of degree zero;
//
//
// no. of nodes (effective graph) < no. of nodes (BGL graph)
// no. of edges (effective graph) = no. of edges (BGL graph)
//
// grid points IDs associated with the polygon(s)
std::vector<Polygon_gp_id> gpoints_id_pgn;
// grid points IDs associated with the graph
std::vector<int> gpoints_id_graph;
// project the data to the grid;
// evaluate the grid points IDs associated with the polygon(s) and
// those associated with the complementary domain (graph)
projectDataToGrid(grid_points, polygons, gpoints_id_pgn, gpoints_id_graph);
// no. of grid points associated with the polygon
int no_gpoints_png = gpoints_id_pgn.at(0).size();
// no. of grid points associated with the graph
int no_gpoints_graph = gpoints_id_graph.size();
// writing output file `Dreses.dat'
std::string outfile_name_1("Dreses.dat");
OutputProcess_Dreses out1(io_specs.getAbsolutePathName(outfile_name_1));
out1.toOutput(ref_points, polygons,
grid_specs, no_gpoints_png, no_gpoints_graph);
grid_points.clear();
polygons.clear();
// names of the nodes (vertices)
std::vector<std::string> node_names;
// edges
std::vector<Edge> edges;
// evaluating the node names and the edges of the `effective graph'
initGraph(grid_specs, gpoints_id_pgn, gpoints_id_graph, node_names, edges);
gpoints_id_pgn.clear();
gpoints_id_graph.clear();
// number of edges
int no_edges;
no_edges = edges.size();
// weights
float* weights = new float[no_edges];
for (int i=0; i<no_edges; i++) {
weights[i] = grid_specs.getGridSpecs().at(2);
}
// BGL graph
GridGraph g(edges.begin(), edges.end(), weights, no_gpoints);
GridGraph g_copy(edges.begin(), edges.end(), weights, no_gpoints);
//--
#ifdef DEBUG_GRAPH
std::cout << "\n>> debug - graph" << std::endl;
std::cout << "no. of nodes (effective graph): " << node_names.size() << std::endl;
std::cout << "no. of nodes (BGL graph): " << no_gpoints << std::endl;
std::cout << "no. of edges: " << edges.size() << std::endl;
write_graphviz(std::cout, g);
#endif // DEBUG_GRAPH
//--
// parents of the nodes
std::vector<vertex_descriptor> parents(num_vertices(g));
// source node ID
// note that node ID = (grid point ID - 1)
int s_node_id;
s_node_id = (getGridPointID(ref_points.at(0).first, ref_points.at(0).second, grid_specs) - 1);
// source node
vertex_descriptor s_node = vertex(s_node_id, g);
// the parent of `s_node' is `s_node' (distance = 0)
parents[s_node] = s_node;
// distances from the source to each node
// (including the null distances - i.e. the distance from the source to itself
// and the distances from the source to the nodes of degree zero)
vertices_size_type distances[no_gpoints];
std::fill_n(distances, no_gpoints, 0);
// evaluating the distances by using the Breadth-First Search (BFS) algorithm
breadth_first_search(g,
s_node,
visitor(make_bfs_visitor(std::make_pair(record_distances(distances,
on_tree_edge()),
std::make_pair(record_predecessors(&parents[0],
on_tree_edge()),
copy_graph(g_copy,
on_examine_edge())
)
)
)
)
);
// writing output file `distances.dat'
std::string outfile_name_2("distances.dat");
OutputProcess_Distances out2(io_specs.getAbsolutePathName(outfile_name_2));
out2.toOutput(grid_specs, no_gpoints, s_node_id, node_names, distances);
delete [] weights;
}