Overview

Induced Subgraph algorithm can compute the corresponding induced subgraph from a given set of nodes and return the edges in that induced subgraph in the form of path. Induced subgraph, as one of the basic concepts in Graph Theory, is commonly used to dig the direct connections between target entities.

Basic Concept

Induced Subgraph

Specifying a set of nodes in the graph as initial nodes, and finding edges which two endpoints are both of those initial nodes, these initial nodes and edges that are found form an induced subgraph.

The endpoints of all red edges in the graph above are both red nodes, while all black edges have at least one endpoint that is not red node, all red nodes and red edges in the graph form an induced subgraph.

Special Case

Lonely Node, Disconnected Graph

Lonely node is valid initial node.

If the given initial nodes are in different connected components of the graph, induced subgraph will be produced in each connected component.

Self-loop Edge

Self-loop edge of the initial node must be one edge in the induced subgraph.

Directed Edge

For directed edges, Induced Subgraph algorithm ignores the direction of edges but calculates them as undirected edges.

Results and Statistics

Take the graph below as an example, run the Induced Subgraph algorithm:

Algorithm results: Given nodes UUID = 1,3,4,7,10, return the induced subgraph (1-hop paths that form the subgraph)

1 -->[102]--> 3
3 -->[105]--> 4
4 -->[106]--> 1
4 -->[107]--> 1
7 -->[109]--> 7

Algorithm statistics: N/A

Command and Configuration

• Command: algo(subgraph)
• Configurations for the parameter params():

Algorithm Execution

Task Writeback

1. File Writeback

Example: Calculate induced subgraph with nodes UUID = 1,3,4,7,10, write the algorithm results back to file named paths

algo(subgraph).params({
  uuids: [1,3,4,7,10]
}).write({
  file:{
    filename: "paths"
    }
})

2. Property Writeback

Not supported by this algorithm.

3. Statistics Writeback

This algorithm has no statistics.

Direct Return

Example: Calculate induced subgraph with nodes UUID = 1,3,4,7,10, define algorithm results as alias named path, and return the results

algo(subgraph).params({
  uuids: [1,3,4,7,10]
}) as path 
return path

Streaming Return

Example: Calculate induced subgraph with nodes UUID = 6,7, return all the information of edges in the subgraph

algo(subgraph).params({
  uuids: [6,7]
}).stream() as p
with pedges(p) as e
find().edges(e) return edges{*}

Real-time Statistics

This algorithm has no statistics.