Weakly Connected Components query module

The wcc.py query module can run WCC analysis on a sub-graph of the whole graph.

get_components(vertices, edges)

This procedure finds weakly connected components of a given subgraph of a directed graph.

The subgraph is defined by a list of vertices and a list of edges which are passed as arguments of the procedure.

Parameters

• vertices (mgp.List[mgp.Vertex]) – A set of vertices of a subgraph containing all vertices provided in a list of vertices along with all vertices that are endpoints of provided edges.

• edges (mgp.List[mgp.Edge]) – A set of edges of a subgraph contains all edges from the list of provided edges.

Returns

The procedure returns 2 fields. The first, n_components, is the number of weakly connected components of the subgraph. The second, components, is a list of weakly connected components. Each component is given as a list of mgp.Vertex objects from that component.

Return type

mgp.Record(n_components=int, components=mgp.List[mgp.List[mgp.Vertex]])

Examples

For example, weakly connected components in a subgraph formed from all vertices labeled Person and edges between such vertices can be obtained using the following openCypher query:

MATCH (n:Person)-[e]->(m:Person)
WITH collect(n) AS nodes, collect(e) AS edges
CALL wcc.get_components(nodes, edges) YIELD *
RETURN n_components, components;