graph_tools

Filename: graph_tools.py

Author: Daisuke Oyama

Tools for dealing with a directed graph.

class quantecon.graph_tools.DiGraph(adj_matrix, weighted=False)[source]

Bases: object

Class for a directed graph. It stores useful information about the graph structure such as strong connectivity [R3] and periodicity [R4].

Parameters:

adj_matrix : array_like(ndim=2)

Adjacency matrix representing a directed graph. Must be of shape n x n.

weighted : bool, optional(default=False)

Whether to treat adj_matrix as a weighted adjacency matrix.

References

[R3](1, 2) Strongly connected component, Wikipedia.
[R4](1, 2) Aperiodic graph, Wikipedia.

Attributes

csgraph (scipy.sparse.csr_matrix) Compressed sparse representation of the digraph.
is_strongly_connected (bool) Indicate whether the digraph is strongly connected.
num_strongly_connected_components (int) The number of the strongly connected components.
strongly_connected_components (list(ndarray(int))) List of numpy arrays containing the strongly connected components.
num_sink_strongly_connected_components (int) The number of the sink strongly connected components.
sink_strongly_connected_components (list(ndarray(int))) List of numpy arrays containing the sink strongly connected components.
is_aperiodic (bool) Indicate whether the digraph is aperiodic.
period (int) The period of the digraph. Defined only for a strongly connected digraph.
cyclic_components (list(ndarray(int))) List of numpy arrays containing the cyclic components.

Methods

subgraph(nodes) Return the subgraph consisting of the given nodes and edges between thses nodes.
cyclic_components
is_aperiodic
is_strongly_connected
num_sink_strongly_connected_components
num_strongly_connected_components
period
scc_proj
sink_scc_labels
sink_strongly_connected_components
strongly_connected_components
subgraph(nodes)[source]

Return the subgraph consisting of the given nodes and edges between thses nodes.

Parameters:

nodes : array_like(int, ndim=1)

Array of nodes.

Returns:

DiGraph

A DiGraph representing the subgraph.