Subgraph

Signal-Subgraph Estimators

class graspologic.subgraph.SignalSubgraph

Estimate the signal-subgraph of a set of labeled graph samples.

The incoherent estimator finds the signal-subgraph, constrained by the number of edges. The coherent estimator finds the signal-subgraph, constrained by the number of edges and by the number of vertices that the edges in the signal-subgraph may be incident to.

Parameters:

graphs: array-like, shape (n_vertices, n_vertices, s_samples)

A series of labeled (n_vertices, n_vertices) unweighted graph samples. If undirected, the upper or lower triangle matrices should be used.

labels: vector, length (s_samples)

A vector of class labels. There must be a maximum of two classes.

Attributes:

contmat_: array-like, shape (n_vertices, n_vertices, 2, 2)

An array that stores the 2-by-2 contingency matrix for each point in the graph samples.

sigsub_: tuple, shape (2, n_edges)

A tuple of a row index array and column index array, where n_edges is the size of the signal-subgraph determined by constraints.

mask_: array-like, shape (n_vertices, n_vertices)

An array of boolean values. Entries are true for edges that are in the signal subgraph.

References

[1]

10. 20. Vogelstein, W. R. Gray, R. J. Vogelstein, and C. E. Priebe, "Graph Classification using Signal-Subgraphs: Applications in Statistical Connectomics," arXiv:1108.1427v2 [stat.AP], 2012.

fit(graphs, labels, constraints)

Fit the signal-subgraph estimator according to the constraints given.

Parameters:

graphs: array-like, shape (n_vertices, n_vertices, s_samples)

A series of labeled (n_vertices, n_vertices) unweighted graph samples. If undirected, the upper or lower triangle matrices should be used.

labels: vector, length (s_samples)

A vector of class labels. There must be a maximum of two classes.

constraints: int or vector

The constraints that will be imposed onto the estimated signal-subgraph.

If constraints is an int, constraints is the number of edges in the signal-subgraph. If constraints is a vector, the first element of constraints is the number of edges in the signal-subgraph, and the second element of constraints is the number of vertices that the signal-subgraph must be incident to.

Returns:

self: returns an instance of self

Parameters:

• graphs (ndarray) --

• labels (List | ndarray) --

• constraints (int | List) --

Return type:

SignalSubgraph

fit_transform(graphs, labels, constraints)

A function to return the indices of the signal-subgraph. If return_mask is True, also returns a mask for the signal-subgraph.

Parameters:

graphs: array-like, shape (n_vertices, n_vertices, s_samples)

A series of labeled (n_vertices, n_vertices) unweighted graph samples. If undirected, the upper or lower triangle matrices should be used.

labels: vector, length (s_samples)

A vector of class labels. There must be a maximum of two classes.

constraints: int or vector

The constraints that will be imposed onto the estimated signal-subgraph.

If constraints is an int, constraints is the number of edges in the signal-subgraph. If constraints is a vector, the first element of constraints is the number of edges in the signal-subgraph, and the second element of constraints is the number of vertices that the signal-subgraph must be incident to.

Returns:

sigsub: tuple

Contains an array of row indices and an array of column indices.

Parameters:

• graphs (ndarray) --

• labels (List | ndarray) --

• constraints (int | List) --

Return type:

Tuple