@graphty/layout/src/layouts/basic/random.ts

graph layout algorithms based on networkx

/**
 * Random layout algorithm
 */

import { Graph, Node, PositionMap } from '../../types';
import { _processParams } from '../../utils/params';
import { getNodesFromGraph } from '../../utils/graph';
import { RandomNumberGenerator } from '../../utils/random';

/**
 * Position nodes uniformly at random in the unit square.
 * 
 * @param G - Graph or list of nodes
 * @param center - Coordinate pair around which to center the layout
 * @param dim - Dimension of layout
 * @param seed - Random seed for reproducible layouts
 * @returns Positions dictionary keyed by node
 */
export function randomLayout(G: Graph | Node[], center: number[] | null = null, dim: number = 2, seed: number | null = null): PositionMap {
  const processed = _processParams(G, center, dim);
  const nodes = getNodesFromGraph(processed.G);
  center = processed.center;

  const rng = new RandomNumberGenerator(seed ?? undefined);
  const pos: PositionMap = {};

  nodes.forEach((node: Node) => {
    pos[node] = (rng.rand(dim) as number[]).map((val: number, i: number) => val + center[i]);
  });

  return pos;
}