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import BarnesHutSolver from './components/physics/BarnesHutSolver';
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import Repulsion from './components/physics/RepulsionSolver';
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import HierarchicalRepulsion from './components/physics/HierarchicalRepulsionSolver';
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import SpringSolver from './components/physics/SpringSolver';
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import HierarchicalSpringSolver from './components/physics/HierarchicalSpringSolver';
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import CentralGravitySolver from './components/physics/CentralGravitySolver';
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import ForceAtlas2BasedRepulsionSolver from './components/physics/FA2BasedRepulsionSolver';
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import ForceAtlas2BasedCentralGravitySolver from './components/physics/FA2BasedCentralGravitySolver';
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class PhysicsWorker {
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constructor(postMessage) {
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this.body = {};
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this.physicsBody = {physicsNodeIndices:[], physicsEdgeIndices:[], forces: {}, velocities: {}};
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this.postMessage = postMessage;
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this.options = {};
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this.stabilized = false;
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this.previousStates = {};
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this.positions = {};
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this.timestep = 0.5;
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}
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handleMessage(event) {
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var msg = event.data;
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switch (msg.type) {
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case 'calculateForces':
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this.calculateForces();
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this.moveNodes();
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this.postMessage({
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type: 'positions',
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data: {
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positions: this.positions,
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stabilized: this.stabilized
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}
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});
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break;
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case 'update':
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let node = this.body.nodes[msg.data.id];
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node.x = msg.data.x;
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node.y = msg.data.y;
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break;
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case 'options':
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this.options = msg.data;
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this.timestep = this.options.timestep;
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this.init();
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break;
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case 'physicsObjects':
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this.body.nodes = msg.data.nodes;
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this.body.edges = msg.data.edges;
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this.updatePhysicsData();
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break;
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default:
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console.warn('unknown message from PhysicsEngine', msg);
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}
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}
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/**
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* configure the engine.
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*/
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init() {
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var options;
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if (this.options.solver === 'forceAtlas2Based') {
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options = this.options.forceAtlas2Based;
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this.nodesSolver = new ForceAtlas2BasedRepulsionSolver(this.body, this.physicsBody, options);
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this.edgesSolver = new SpringSolver(this.body, this.physicsBody, options);
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this.gravitySolver = new ForceAtlas2BasedCentralGravitySolver(this.body, this.physicsBody, options);
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}
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else if (this.options.solver === 'repulsion') {
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options = this.options.repulsion;
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this.nodesSolver = new Repulsion(this.body, this.physicsBody, options);
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this.edgesSolver = new SpringSolver(this.body, this.physicsBody, options);
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this.gravitySolver = new CentralGravitySolver(this.body, this.physicsBody, options);
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}
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else if (this.options.solver === 'hierarchicalRepulsion') {
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options = this.options.hierarchicalRepulsion;
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this.nodesSolver = new HierarchicalRepulsion(this.body, this.physicsBody, options);
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this.edgesSolver = new HierarchicalSpringSolver(this.body, this.physicsBody, options);
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this.gravitySolver = new CentralGravitySolver(this.body, this.physicsBody, options);
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}
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else { // barnesHut
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options = this.options.barnesHut;
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this.nodesSolver = new BarnesHutSolver(this.body, this.physicsBody, options);
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this.edgesSolver = new SpringSolver(this.body, this.physicsBody, options);
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this.gravitySolver = new CentralGravitySolver(this.body, this.physicsBody, options);
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}
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this.modelOptions = options;
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}
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/**
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* Nodes and edges can have the physics toggles on or off. A collection of indices is created here so we can skip the check all the time.
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*
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* @private
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*/
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updatePhysicsData() {
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this.physicsBody.forces = {};
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this.physicsBody.physicsNodeIndices = [];
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this.physicsBody.physicsEdgeIndices = [];
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let nodes = this.body.nodes;
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let edges = this.body.edges;
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// get node indices for physics
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for (let nodeId in nodes) {
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if (nodes.hasOwnProperty(nodeId)) {
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this.physicsBody.physicsNodeIndices.push(nodeId);
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this.positions[nodeId] = {
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x: nodes[nodeId].x,
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y: nodes[nodeId].y
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}
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}
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}
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// get edge indices for physics
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for (let edgeId in edges) {
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if (edges.hasOwnProperty(edgeId)) {
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this.physicsBody.physicsEdgeIndices.push(edgeId);
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}
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}
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// get the velocity and the forces vector
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for (let i = 0; i < this.physicsBody.physicsNodeIndices.length; i++) {
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let nodeId = this.physicsBody.physicsNodeIndices[i];
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this.physicsBody.forces[nodeId] = {x: 0, y: 0};
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// forces can be reset because they are recalculated. Velocities have to persist.
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if (this.physicsBody.velocities[nodeId] === undefined) {
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this.physicsBody.velocities[nodeId] = {x: 0, y: 0};
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}
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}
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// clean deleted nodes from the velocity vector
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for (let nodeId in this.physicsBody.velocities) {
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if (nodes[nodeId] === undefined) {
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delete this.physicsBody.velocities[nodeId];
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}
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}
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// console.log(this.physicsBody);
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}
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/**
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* move the nodes one timestap and check if they are stabilized
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* @returns {boolean}
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*/
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moveNodes() {
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var nodeIndices = this.physicsBody.physicsNodeIndices;
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var maxVelocity = this.options.maxVelocity ? this.options.maxVelocity : 1e9;
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var maxNodeVelocity = 0;
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for (let i = 0; i < nodeIndices.length; i++) {
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let nodeId = nodeIndices[i];
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let nodeVelocity = this._performStep(nodeId, maxVelocity);
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// stabilized is true if stabilized is true and velocity is smaller than vmin --> all nodes must be stabilized
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maxNodeVelocity = Math.max(maxNodeVelocity,nodeVelocity);
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}
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// evaluating the stabilized and adaptiveTimestepEnabled conditions
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this.stabilized = maxNodeVelocity < this.options.minVelocity;
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}
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/**
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* Perform the actual step
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*
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* @param nodeId
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* @param maxVelocity
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* @returns {number}
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* @private
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*/
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_performStep(nodeId,maxVelocity) {
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let node = this.body.nodes[nodeId];
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let timestep = this.timestep;
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let forces = this.physicsBody.forces;
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let velocities = this.physicsBody.velocities;
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// store the state so we can revert
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this.previousStates[nodeId] = {x:node.x, y:node.y, vx:velocities[nodeId].x, vy:velocities[nodeId].y};
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if (node.options.fixed.x === false) {
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let dx = this.modelOptions.damping * velocities[nodeId].x; // damping force
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let ax = (forces[nodeId].x - dx) / node.options.mass; // acceleration
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velocities[nodeId].x += ax * timestep; // velocity
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velocities[nodeId].x = (Math.abs(velocities[nodeId].x) > maxVelocity) ? ((velocities[nodeId].x > 0) ? maxVelocity : -maxVelocity) : velocities[nodeId].x;
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node.x += velocities[nodeId].x * timestep; // position
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this.positions[nodeId].x = node.x;
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}
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else {
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forces[nodeId].x = 0;
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velocities[nodeId].x = 0;
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}
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if (node.options.fixed.y === false) {
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let dy = this.modelOptions.damping * velocities[nodeId].y; // damping force
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let ay = (forces[nodeId].y - dy) / node.options.mass; // acceleration
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velocities[nodeId].y += ay * timestep; // velocity
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velocities[nodeId].y = (Math.abs(velocities[nodeId].y) > maxVelocity) ? ((velocities[nodeId].y > 0) ? maxVelocity : -maxVelocity) : velocities[nodeId].y;
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node.y += velocities[nodeId].y * timestep; // position
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this.positions[nodeId].y = node.y;
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}
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else {
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forces[nodeId].y = 0;
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velocities[nodeId].y = 0;
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}
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let totalVelocity = Math.sqrt(Math.pow(velocities[nodeId].x,2) + Math.pow(velocities[nodeId].y,2));
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return totalVelocity;
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}
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/**
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* calculate the forces for one physics iteration.
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*/
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calculateForces() {
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this.gravitySolver.solve();
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this.nodesSolver.solve();
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this.edgesSolver.solve();
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}
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}
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export default PhysicsWorker;
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