Graphology ForceAtlas2

JavaScript implementation of the ForceAtlas2 algorithm for graphology.

Reference

Jacomy M, Venturini T, Heymann S, Bastian M (2014) ForceAtlas2, a Continuous Graph Layout Algorithm for Handy Network Visualization Designed for the Gephi Software. PLoS ONE 9(6): e98679. https://doi.org/10.1371/journal.pone.0098679

Installation

npm install graphology-layout-forceatlas2

Usage

• Settings
• Synchronous layout
• Webworker
• #.inferSettings

Settings

• adjustSizes ?boolean [false]: should the node's sizes be taken into account?
• barnesHutOptimize ?boolean [false]: whether to use the Barnes-Hut approximation to compute repulsion in O(n*log(n)) rather than default O(n^2), n being the number of nodes.
• barnesHutTheta ?number [0.5]: Barnes-Hut approximation theta parameter.
• edgeWeightInfluence ?number [0]: influence of the edge's weights on the layout.
• gravity ?number [1]: strength of the layout's gravity.
• linLogMode ?boolean [false]: whether to use Noack's LinLog model.
• outboundAttractionDistribution ?boolean [false]
• scalingRatio ?number [1]
• slowDown ?number [1]
• strongGravityMode ?boolean [false]

Synchronous layout

import forceAtlas2 from 'graphology-layout-forceatlas2';

const positions = forceAtlas2(graph, {iterations: 50});

// With settings:
const positions = forceAtlas2(graph, {
  iterations: 50,
  settings: {
    gravity: 10
  }
});

// To directly assign the positions to the nodes:
forceAtlas2.assign(graph);

Arguments

• graph Graph: target graph.
• options object: options:
  • iterations number: number of iterations to perform.
  • settings ?object: the layout's settings (see #settings).

Webworker

If you need to run the layout's computation in a web worker, the library comes with a utility to do so:

Example

import FA2Layout from 'graphology-layout-forceatlas2/worker';

const layout = new FA2Layout(graph);

// To start the layout
layout.start({settings: {gravity: 1}});

// To stop the layout
layout.stop();

// To kill the layout and release attached memory
layout.kill();

#.inferSettings

If you don't know how to tune the layout's settings and want to infer them from your graph, you can use the #.inferSettings method:

import forceAtlas2 from 'graphology-layout-forceatlas2';

const saneSettings = forceAtlas2.inferSettings(graph);
const positions = forceAtlas2(graph, {iterations: 50, settings: saneSettings});