xgi.core.globalviews

View of Hypergraphs as a subhypergraph or read-only.

In some algorithms it is convenient to temporarily morph a hypergraph to exclude some nodes or edges. It should be better to do that via a view than to remove and then re-add. This module provides those graph views.

The resulting views are essentially read-only graphs that report data from the original graph object.

Note: Since globalviews look like hypergraphs, one can end up with view-of-view-of-view chains. Be careful with chains because they become very slow with about 15 nested views. Often it is easiest to use .copy() to avoid chains.

Functions

xgi.core.globalviews.subhypergraph(H, nodes=None, edges=None, keep_isolates=True)[source]

View of H applying a filter on nodes and edges.

subhypergraph_view provides a read-only view of the induced subhypergraph that includes nodes, edges, or both based on what the user specifies. This function automatically filters out edges that are not subsets of the nodes. This function may create isolated nodes.

If the user only specifies the nodes to include, the function returns an induced subhypergraph on the nodes.

If the user only specifies the edges to include, the function returns all of the nodes and the specified edges.

If the user specifies both nodes and edges to include in the subhypergraph, then the function returns a subhypergraph with the specified nodes and edges from the list of specified hyperedges that are induced by the specified nodes.

Parameters:

  • H (hypergraph.Hypergraph) – A hypergraph

  • nodes (list or set, optional) – A list of the nodes desired for the subhypergraph. If None (default), uses all the nodes.

  • edges (list or set, optional) – A list of the edges desired for the subhypergraph. If None (default), uses all the edges.

  • keep_isolates (bool, optional) – Whether to keep isolated nodes in the subhypergraph. By default, True.

Returns:

A read-only hypergraph view of the input hypergraph.

Return type:

Hypergraph object