arc_graph - graph with nodes corresponding to arcs
arc_graph returns the directed graph g1 with the nodes corresponding to the arcs of the directed graph g. g1 is defined in the following way:
- its nodes correspond to the arcs of g
- 2 nodes of the new graph are adjacent if and only if the corresponding arcs of the graph g are consecutive.
The coordinates of the nodes of g1 are given by the middle points of the corresponding edges of g.
If such an arc graph does not exist, an empty vector is returned.
ta=[1 1 2 4 4 5 6 7 2 3 5 1];
he=[2 6 3 6 7 8 8 8 4 7 3 5];
g=make_graph('foo',1,8,ta,he);
g('node_x')=[281 284 360 185 405 182 118 45];
g('node_y')=[262 179 130 154 368 248 64 309];
show_graph(g);
g1=arc_graph(g);
show_graph(g1,'new');