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');