Network Diffusion

Network

This intentionally abstract simulation depicts the dynamics of a network tending toward the mean. Each agent is connected to its closest geographic neighbors, and possibly a few other random agents in the network, depending on the value of REWIRING_PROBABILITY. With each tick of the simulation, an agent that is larger than its neighbor will transfer some of its size to the neighbor, shrinking the agent and growing the neighbor. With enough time, the network reaches stasis.

Try adjusting the parameters to see how it affects the network dynamics.

💻 diffusion.js - Interactive Editor

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import { Agent, Environment, CanvasRenderer, utils, Network, LineChartRenderer } from "flocc";

/* ----- PARAMETERS ----- */
const POPULATION = 60;
const REWIRING_PROBABILITY = 0.2;
const TRANSFER = 0.02;

/* ----- SETUP ----- */
const environment = new Environment();
const network = new Network();
environment.use(network);

const renderer = new CanvasRenderer(environment, {
  autoPosition: true,
  width: 400,
  height: 400
});
renderer.mount("#container");
const chart = new LineChartRenderer(environment, {
  autoScale: true,
  background: "#eee",
  width: 300,
  height: 300,
  range: { min: -0.25, max: 1 }
});
chart.mount("#chart");

function tick(agent) {
  const neighbors = network.neighbors(agent);
  neighbors.forEach(neighbor => {
    if (neighbor.get("size") + TRANSFER < agent.get("size")) {
      agent.decrement("size", TRANSFER);
      neighbor.increment("size", TRANSFER);
    }
  });
}

function setup() {
  for (let i = 0; i < POPULATION; i++) {
    const agent = new Agent();
    agent.set("size", Math.max(utils.gaussian(7, 6), 1));
    agent.addRule(tick);
    environment.addAgent(agent);
    network.addAgent(agent);
  }

  for (let i = 0; i < POPULATION; i++) {
    for (let j = i - 2; j < i + 2; j++) {
      network.connect(network.get(i), network.get(j));
    }
  }

  network.agents.forEach((agent, i) => {
    network.neighbors(agent).forEach(neighbor => {
      if (Math.random() < REWIRING_PROBABILITY) {
        network.disconnect(agent, neighbor);

        const j = Math.floor(Math.random() * POPULATION);
        network.connect(agent, network.get(j));
      }
    });
  });

  chart.metric("size", {
    fn: utils.stdDev
  });

  chart.metric("size", {
    color: "blue",
    fn: utils.max
  });

  chart.metric("size", {
    color: "red",
    fn: utils.min
  });
}

function draw() {
  environment.tick();
  requestAnimationFrame(draw);
}

setup();
draw();

Edit the code on the left · See results on the right