Graph Functions

ReGraph exposes a number of powerful graph analysis functions to add insight to your data. These functions are in the 'regraph/analysis' package.

The example below shows how to remove singletons (nodes without any neighbors) from your data using the degrees function, which returns the number of neighbors each item has.

import React from 'react';
import { Chart} from 'regraph';
import { degrees } from 'regraph/analysis';

async function removeSingletons(items) {
  const neighbors = await degrees(items);
  const filtered = { ...items };
  for (var id in neighbors) {
    if (neighbors[id] < 1) {
      delete filtered[id];
    }
  }
  return filtered;
}

function FilteredChart() {
  const [items, setItems] = React.useState(getData());
  const filter = async () => {
    const filtered = await removeSingletons(items);
    setItems(filtered);
  };

  return (
    <div style={{ width: '100%', height: '100%' }}>
      <button onClick={filter}>Filter</button>
      <Chart items={items} />
    </div>
  );
}

By default, graph functions run on nodes and links in the underlying chart level and ignore combos, summary links and aggregate links. For more details, see the Graph Analysis documentation.

betweenness(items, options)

Calculates the betweenness centrality of all nodes in the graph.

Parameters

items: object; The items to analyze.
options: object; Various options which define whether the graph is directed, the result normalized and values associated with the links.

Returns Promise

Returns a Promise which resolves to a dictionary whose properties are the ids of the nodes in the graph. The values are the betweenness values.

closeness(items, options)

Calculates the closeness centrality of all nodes in the graph.

Parameters

items: object; The items to analyze.
options: object; Options which define whether the graph is directed, the result normalized and values associated with the links.

Returns Promise

Returns a Promise which resolves to a dictionary whose properties are the ids of the nodes in the graph. The values are the closeness values.

clusters(items, options)

Groups nodes in the graph into a set of clusters, and then returns an object describing them.

Parameters

items: object; The items to analyze.
options: object; Options which special rules for the clusters calculation.

Returns Promise

Returns a Promise which resolves to an array of dictionaries, one entry for each cluster. The values of each dictionary are the items in that cluster.

components(items)

Returns the separate 'connected components' of the graph.

Parameters

items: object; The items to analyze.

Returns Promise

Returns a Promise which resolves to an array of dictionaries, one entry for each component. The values of each dictionary are the items in that component.

degrees(items, options)

Calculates the degrees (number of links) of all nodes in the graph.

Parameters

items: object; The items to analyze.
options: object; Options which define the direction and values associated with the links.

Returns Promise

Returns a Promise which resolves to an object whose properties are the ids of the nodes, the values of which are the degree values.

distances(items, id, options)

Calculates the distances of all nodes from the node specified. The distance is the number of edges in a shortest path.

Parameters

items: object; The items to analyze.
id: string; The id of the node to start from.
options: object; Options for the direction and values associated with the paths.

Returns Promise

Returns a Promise which resolves to a dictionary object, where the properties are the ids of the nodes and the values are the distances.

eigenCentrality(items, options)

Computes the eigenvector centrality of each node.

Parameters

items: object; The items to analyze.
options: object; Options which define special rules for the eigencentrality computation.

Returns Promise

Returns a Promise which resolves to a dictionary object, where the properties are the ids of the nodes and the values are the eigenvector centralities.

kCores(items)

Calculates subgraphs of the graph where each node has a degree at least k. It works by successively removing nodes of degree less than k until no further nodes can be removed.

Parameters

items: object; The items to analyze.

Returns Promise

Returns a Promise which resolves to an object which describes the kCores found.

neighbors(items, id, options)

Calculates the list of neighboring (i.e. linked) items to the ids supplied.

Parameters

items: object; The items to analyze.
id: string | array of strings | object; The items whose neighbors should be found. Can be either a string id, an array of string ids, or an object of items (indexed by id).
options: object; Options which define special rules for items iteration.

Returns Promise

Returns a Promise which resolves to a dictionary of neighboring items.

pageRank(items, options)

Computes the Page Rank of each node.

Parameters

items: object; The items to analyze.
options: object; Options which define special rules for the Page Rank computation.

Returns Promise

Returns a Promise which resolves to a dictionary object, where the properties are the ids of the nodes and the values are the Page Rank scores.

shortestPaths(items, id1, id2, options)

Calculates all the shortest paths between the nodes specified.

Parameters

items: object; The items to analyze.
id1: string; The id of the starting node on the path.
id2: string; The id of the ending node on the path.
options: object; Various options for the direction and values associated with the paths.

Returns Promise<ShortestPathsResult>

Returns a Promise which resolves to an object which describes the path structure.

ShortestPathsResult

distance

required

number

The length of the shortest path - more precisely the combined link value of the path.

items

required

object

A dictionary whose properties are the ids of items on the shortest paths. The values are the item definitions.

one

required

array of strings

An array of ids describing the same path as onePath, but containing nodes only. Includes the start and end nodes.

onePath

required

array of strings

One of the shortest paths found - returned an array of alternating node and link ids. Includes the start and end nodes.