Sage Reference Manual: Graph Theory - Mirrors

Sage Reference Manual: Graph Theory, Release 6.1.1
The empty graph is a subgraph of every graph:
sage: g.subgraph_search_count(graphs.EmptyGraph())
1
TESTS:
Inside of a small graph (trac ticket #13906):
sage: Graph(5).subgraph_search_count(Graph(1))
5
subgraph_search_iterator(G, induced=False)
Returns an iterator over the labelled copies of G in self.
INPUT:
•G – the graph whose copies we are looking for in self.
•induced – boolean (default: False). Whether or not to iterate over the induced copies of G in
self.
ALGORITHM:
Brute-force search.
OUTPUT:
Iterator over the labelled copies of G in self, as lists. For each value (v 1 , v 2 , ..., v k ) returned,
the first vertex of G is associated with v 1 , the second with v 2 , etc ...
Note: This method also works on digraphs.
See Also:
•subgraph_search() – finds an subgraph isomorphic to H inside of a graph G
•subgraph_search_count() – Counts the number of copies of a graph H inside of a graph G
EXAMPLE:
Iterating through all the labelled P 3 of P 5 :
sage: g = graphs.PathGraph(5)
sage: for p in g.subgraph_search_iterator(graphs.PathGraph(3)):
... print p
[0, 1, 2]
[1, 2, 3]
[2, 1, 0]
[2, 3, 4]
[3, 2, 1]
[4, 3, 2]
TESTS:
Inside of a small graph (trac ticket #13906):
sage: list(Graph(5).subgraph_search_iterator(Graph(1)))
[Graph on 1 vertex, Graph on 1 vertex, Graph on 1 vertex, Graph on 1 vertex, Graph on 1 vert
szeged_index()
Returns the Szeged index of the graph.
152 Chapter 1. Graph objects and methods