find_induced_nodes#
- find_induced_nodes(G, s, t, treewidth_bound=9223372036854775807)[source]#
Returns the set of induced nodes in the path from s to t.
- Parameters:
- Ggraph
A chordal NetworkX graph
- snode
Source node to look for induced nodes
- tnode
Destination node to look for induced nodes
- treewidth_bound: float
Maximum treewidth acceptable for the graph H. The search for induced nodes will end as soon as the treewidth_bound is exceeded.
- Returns:
- induced_nodesSet of nodes
The set of induced nodes in the path from s to t in G
- Raises:
- NetworkXError
The algorithm does not support DiGraph, MultiGraph and MultiDiGraph. If the input graph is an instance of one of these classes, a
NetworkXError
is raised. The algorithm can only be applied to chordal graphs. If the input graph is found to be non-chordal, aNetworkXError
is raised.
Notes
G must be a chordal graph and (s,t) an edge that is not in G.
If a treewidth_bound is provided, the search for induced nodes will end as soon as the treewidth_bound is exceeded.
The algorithm is inspired by Algorithm 4 in [1]. A formal definition of induced node can also be found on that reference.
References
[1]Learning Bounded Treewidth Bayesian Networks. Gal Elidan, Stephen Gould; JMLR, 9(Dec):2699–2731, 2008. http://jmlr.csail.mit.edu/papers/volume9/elidan08a/elidan08a.pdf
Examples
>>> G = nx.Graph() >>> G = nx.generators.classic.path_graph(10) >>> induced_nodes = nx.find_induced_nodes(G, 1, 9, 2) >>> sorted(induced_nodes) [1, 2, 3, 4, 5, 6, 7, 8, 9]