graph_tool.generation.graph_union(g1, g2, intersection=None, props=None, include=False, internal_props=False)[source]#

Return the union of graphs g1 and g2, composed of all edges and vertices of g1 and g2, without overlap (if intersection == None).


First graph in the union.


Second graph in the union.

intersectionVertexPropertyMap (optional, default: None)

Vertex property map owned by g2 which maps each of its vertices to vertex indices belonging to g1. Negative values mean no mapping exists, and thus both vertices in g1 and g2 will be present in the union graph.

propslist of tuples of PropertyMap (optional, default: None)

Each element in this list must be a tuple of two PropertyMap objects. The first element must be a property of g1, and the second of g2. If either value is None, an empty map is created. The values of the property maps are propagated into the union graph, and returned.

includebool (optional, default: False)

If True, graph g2 is inserted in-place into g1, which is modified. If False, a new graph is created, and both graphs remain unmodified.

internal_propsbool (optional, default: False)

If True, all internal property maps are propagated, in addition to props.


The union graph

propslist of PropertyMap objects

List of propagated properties. This is only returned if props is not empty.


>>> g = gt.triangulation(random((300,2)))[0]
>>> ug = gt.graph_union(g, g)
>>> uug = gt.graph_union(g, ug)
>>> pos = gt.sfdp_layout(g)
>>> gt.graph_draw(g, pos=pos, adjust_aspect=False, output="graph_original.pdf")
>>> pos = gt.sfdp_layout(ug)
>>> gt.graph_draw(ug, pos=pos, adjust_aspect=False, output="graph_union.pdf")
>>> pos = gt.sfdp_layout(uug)
>>> gt.graph_draw(uug, pos=pos, adjust_aspect=False, output="graph_union2.pdf")
../_images/graph_original.png ../_images/graph_union.png ../_images/graph_union2.png