Force-directed graph is working

src/classes/display/box.js

@@ -1,6 +1,6 @@
 import { DisplayValue } from './display-value.js';
 import { randomID } from '../../util/helpers.js';
-import { Rectangle, Vector } from './geometry.js';
+import { Rectangle, Vector } from '../supporting/geometry/index.js';
 
 export class Box {
   constructor(name, parentEl, options = {}) {
@@ -61,7 +61,7 @@ export class Box {
     return this.el.id;
   }
 
-  getGeometry() {
+  get rect() {
     const {
       width, height,
     } = this.el.getBoundingClientRect();

src/classes/display/force-directed.js

@@ -1,18 +1,16 @@
 import {
-  DEFAULT_OVERLAP_FORCE,
-  DEFAULT_TARGET_RADIUS,
   DEFAULT_TIME_STEP,
-  DISTANCE_FACTOR,
+  MINIMUM_VELOCITY,
-  EPSILON,
-  MINIMUM_FORCE,
   VISCOSITY_FACTOR,
   TIME_DILATION_FACTOR,
-  MINIMUM_VELOCITY,
+  MAX_STEPS_TO_EQUILIBRIUM,
+  TRANSLATION_VELOCITY_FACTOR,
 } from '../../util/constants.js';
 import { Edge } from '../supporting/edge.js';
 import { WeightedDirectedGraph } from '../supporting/wdg.js';
 import { Box } from './box.js';
-import { Rectangle, Vector } from './geometry.js';
+import { Vector, Rectangle } from '../supporting/geometry/index.js';
+import { overlapRepulsionForce, targetRadiusForce } from './pairwise-forces.js';
 
 // Render children with absolute css positioning.
 
@@ -39,15 +37,17 @@ import { Rectangle, Vector } from './geometry.js';
 // NOTE: When mouse is in our box, we could hijack the scroll actions to zoom in/out.
 
 export class ForceDirectedGraph extends WeightedDirectedGraph {
-  constructor(name, parentEl, options = {}) {
+  constructor(name, parentEl, { width = 800, height = 600, ...options } = {}) {
     super(name, options);
     this.box = new Box(name, parentEl, options);
     this.box.addClass('fixed');
     this.box.addClass('force-directed-graph');
     this.intervalTask = null;
     this.canvas = window.document.createElement('canvas');
-    this.box.el.style.width = `${options.width ?? 800}px`;
+    this.width = width;
-    this.box.el.style.height = `${options.height ?? 600}px`;
+    this.height = height;
+    this.box.el.style.width = `${width}px`;
+    this.box.el.style.height = `${height}px`;
     this.box.el.appendChild(this.canvas);
     this.fitCanvasToGraph();
     this.nodes = [];
@@ -55,23 +55,65 @@ export class ForceDirectedGraph extends WeightedDirectedGraph {
   }
 
   fitCanvasToGraph() {
-    [this.canvas.width, this.canvas.height] = this.box.getGeometry().dimensions;
+    [this.canvas.width, this.canvas.height] = this.box.rect.dimensions;
   }
 
+  // addVertex(type, id, data, label, options) {
   addVertex(...args) {
     const vertex = super.addVertex(...args);
     const box = this.box.addBox(vertex.id);
+
+    // Link from the graph vertex to the corresponding display box
+    vertex.box = box;
+
+    // Link from the display box to the corresponding graph vertex
+    box.vertex = vertex;
+
     box.addClass('absolute');
     box.addClass('vertex');
     box.el.style.left = '0px';
     box.el.style.top = '0px';
     box.velocity = Vector.from([0, 0]);
     box.setInnerHTML(vertex.getHTML());
-    box.vertex = vertex;
     this.nodes.push(box);
+
+    // When vertex properties are updated, re-render the node contents
     vertex.onUpdate = () => {
       box.setInnerHTML(vertex.getHTML());
+      // Maybe resolve forces
+      this.runUntilEquilibrium();
     };
+
+    this.runUntilEquilibrium();
+
+    // Allow moving vertices with the mouse
+    box.el.addEventListener('mousedown', (e) => {
+      if (!this.mouseMoving) {
+        e.preventDefault();
+        // Record current mouse position
+        this.mousePosition = Vector.from([e.clientX, e.clientY]);
+        // Begin tracking mouse movement
+        this.mouseMoving = box;
+      }
+    });
+    document.addEventListener('mousemove', (e) => {
+      if (this.mouseMoving === box) {
+        const mousePosition = Vector.from([e.clientX, e.clientY]);
+        // Apply translation
+        box.move(mousePosition.subtract(this.mousePosition));
+        // Update current mouse position
+        this.mousePosition = mousePosition;
+        // Equilibrate
+        this.runUntilEquilibrium();
+      }
+    });
+    document.addEventListener('mouseup', () => {
+      // Stop tracking mouse movement
+      this.mouseMoving = null;
+      // Equilibrate
+      this.runUntilEquilibrium();
+    });
+
     return vertex;
   }
 
@@ -83,15 +125,28 @@ export class ForceDirectedGraph extends WeightedDirectedGraph {
 
     const edge = super.addEdge(type, from, to, ...rest);
     const box = this.box.addBox(Edge.getKey({ from, to, type }));
+
+    edge.box = box;
+    box.edge = edge;
+
     box.addClass('absolute');
     box.addClass('edge');
-    // TODO: Center between nodes
+
-    box.el.style.left = '0px';
-    box.el.style.top = '0px';
-    box.velocity = Vector.from([0, 0]);
     box.setInnerHTML(edge.getHTML());
-    box.edge = edge;
     this.edges.push(box);
+
+    // Center between nodes, by applying an attraction force from the edge node
+    // to its `from` and `to` nodes.
+    // We can also initially place it near the midpoint between the `from` and `to` nodes.
+    const midpoint = fromBox.rect.center.add(toBox.rect.center).scale(0.5);
+    const startPosition = midpoint.subtract(box.rect.dimensions.scale(0.5));
+    console.log({
+      fromBox, toBox, midpoint, startPosition, dimensions: box.rect.dimensions,
+    });
+    box.move(startPosition);
+    box.velocity = Vector.from([0, 0]);
+    this.runUntilEquilibrium();
+
     return edge;
   }
 
@@ -101,35 +156,22 @@ export class ForceDirectedGraph extends WeightedDirectedGraph {
     return edge;
   }
 
-  static pairwiseForce(boxA, boxB, targetRadius) {
-    const rectA = boxA instanceof Rectangle ? boxA : boxA.getGeometry();
-    const centerA = rectA.center;
-    const rectB = boxB instanceof Rectangle ? boxB : boxB.getGeometry();
-    const centerB = rectB.center;
-    const r = centerB.subtract(centerA);
-
-    // Apply a stronger force when overlap occurs
-    if (rectA.doesOverlap(rectB)) {
-      // if their centers actually coincide we can just randomize the direction.
-      if (r.magnitudeSquared === 0) {
-        return Vector.randomUnitVector(rectA.dim).scale(DEFAULT_OVERLAP_FORCE);
-      }
-      return r.normalize().scale(DEFAULT_OVERLAP_FORCE);
-    }
-    // repel if closer than targetRadius
-    // attract if farther than targetRadius
-    const force = -DISTANCE_FACTOR * (r.magnitude - targetRadius);
-    return r.normalize().scale(force);
-  }
-
   async runUntilEquilibrium(tDelta = DEFAULT_TIME_STEP) {
+    this.steps = 0;
     if (this.intervalTask) {
       return Promise.resolve();
     }
-    return new Promise((resolve) => {
+    return new Promise((resolve, reject) => {
       this.intervalTask = setInterval(() => {
+        this.steps++;
+        if (this.steps > MAX_STEPS_TO_EQUILIBRIUM) {
+          clearInterval(this.intervalTask);
+          this.intervalTask = null;
+          reject(new Error('Exceeded map steps to reach equilibrium'));
+        }
         const { atEquilibrium } = this.computeEulerFrame(tDelta);
         if (atEquilibrium) {
+          console.log(`Reached equilibrium after ${this.steps} steps`);
           clearInterval(this.intervalTask);
           this.intervalTask = null;
           resolve();
@@ -139,53 +181,99 @@ export class ForceDirectedGraph extends WeightedDirectedGraph {
   }
 
   computeEulerFrame(tDelta = DEFAULT_TIME_STEP) {
-    // Compute all net forces
+    // Compute net forces on each box in the graph
-    const netForces = Array.from(Array(this.nodes.length), () => Vector.from([0, 0]));
+    const boxes = [...this.nodes, ...this.edges];
-    let atEquilibrium = true;
+
+    // Initialize net force vectors
+    for (const box of boxes) {
+      box.netForce = Vector.zeros(2);
+    }
+
+    // Compute overlap repulsion forces among node boxes
     for (const boxA of this.nodes) {
-      const idxA = this.nodes.indexOf(boxA);
+      const idxA = boxes.indexOf(boxA);
       for (const boxB of this.nodes.slice(idxA + 1)) {
-        const idxB = this.nodes.indexOf(boxB);
+        const force = overlapRepulsionForce(boxA, boxB);
-        const force = ForceDirectedGraph.pairwiseForce(boxA, boxB, DEFAULT_TARGET_RADIUS);
+        boxA.netForce = boxA.netForce.subtract(force);
-        // Ignore forces below a certain threshold
+        boxB.netForce = boxB.netForce.add(force);
-        if (force.magnitude >= MINIMUM_FORCE) {
-          netForces[idxA] = netForces[idxA].subtract(force);
-          netForces[idxB] = netForces[idxB].add(force);
-        }
       }
     }
 
-    // Compute motions
+    // Compute pairwise forces among nodes
-    for (const box of this.nodes) {
+    for (const boxA of this.nodes) {
-      const idx = this.nodes.indexOf(box);
+      const idxA = this.nodes.indexOf(boxA);
-      box.velocity = box.velocity.add(netForces[idx].scale(tDelta));
+      for (const boxB of this.nodes.slice(idxA + 1)) {
+        const force = targetRadiusForce(boxA, boxB);
+        boxA.netForce = boxA.netForce.subtract(force);
+        boxB.netForce = boxB.netForce.add(force);
+      }
+    }
+
+    // Compute forces on edge boxes:
+    // Attraction to the `from` and `to` nodes
+    for (const edgeBox of this.edges) {
+      const { edge } = edgeBox;
+      const fromBox = edge.from.box;
+      const toBox = edge.to.box;
+      edgeBox.netForce = edgeBox.netForce
+        .subtract(targetRadiusForce(edgeBox, fromBox, 0))
+        .subtract(targetRadiusForce(edgeBox, toBox, 0));
+    }
+
+    // Do not apply forces to a box if it is being moved by the mouse
+    for (const box of boxes) {
+      if (this.mouseMoving === box) {
+        box.netForce = Vector.zeros(2);
+      }
+    }
+
+    // Compute velocities
+    for (const box of boxes) {
+      box.velocity = box.velocity.add(box.netForce.scale(tDelta));
       // Apply some drag
       box.velocity = box.velocity.scale(1 - VISCOSITY_FACTOR);
     }
 
-    for (const box of this.nodes) {
+    // When all velocities are below MINIMUM_VELOCITY, we have reached equilibrium.
+    let atEquilibrium = true;
+
+    // Apply velocities
+    for (const box of boxes) {
       if (box.velocity.magnitude >= MINIMUM_VELOCITY) {
         atEquilibrium = false;
         box.move(box.velocity);
       }
     }
 
-    // Translate everything to keep coordinates positive
+    // Center the items by computing the bounding box and centering that
-    // TODO: Consider centering and scaling to viewport size
+    if (!this.mouseMoving) {
-    const topLeft = this.box.getGeometry().startPoint;
+      const topLeft = Vector.from(boxes[0].position);
-    const translate = Vector.zeros(2);
+      const bottomRight = Vector.from(boxes[0].position);
-    for (const box of this.nodes) {
+      for (const box of boxes) {
-      const rect = box.getGeometry();
+        for (const vertex of box.rect.vertices) {
-      for (const vertex of rect.vertices) {
+          topLeft[0] = Math.min(topLeft[0], vertex[0]);
-        translate[0] = Math.max(translate[0], topLeft[0] - vertex[0]);
+          topLeft[1] = Math.min(topLeft[1], vertex[1]);
-        translate[1] = Math.max(translate[1], topLeft[1] - vertex[1]);
+
+          bottomRight[0] = Math.max(bottomRight[0], vertex[0]);
+          bottomRight[1] = Math.max(bottomRight[1], vertex[1]);
+        }
+      }
+      const boundingBox = new Rectangle(topLeft, bottomRight.subtract(topLeft));
+      const graphCenter = Vector.from([this.width, this.height]).scale(0.5);
+      const offset = graphCenter.subtract(boundingBox.center);
+      const translate = offset.scale(TRANSLATION_VELOCITY_FACTOR);
+
+      if (translate.magnitude >= MINIMUM_VELOCITY) {
+        atEquilibrium = false;
+
+        // Apply translations
+        for (const box of boxes) {
+          box.move(translate);
+        }
       }
     }
-    for (const box of this.nodes) {
-      box.move(translate);
-    }
 
-    this.fitCanvasToGraph();
+    // TODO: Scaling to fit
 
     return { atEquilibrium };
   }

src/classes/display/geometry.js

@@ -1,100 +0,0 @@
-export class Vector extends Array {
-  get dim() {
-    return this.length ?? 0;
-  }
-
-  add(vector) {
-    if (vector.dim !== this.dim) {
-      throw new Error('Can only add vectors of the same dimensions');
-    }
-    return Vector.from(this.map((q, idx) => q + vector[idx]));
-  }
-
-  subtract(vector) {
-    if (vector.dim !== this.dim) {
-      throw new Error('Can only subtract vectors of the same dimensions');
-    }
-    return Vector.from(this.map((q, idx) => q - vector[idx]));
-  }
-
-  static unitVector(dim, totalDim) {
-    return Vector.from(Array(totalDim), (_, idx) => (idx === dim ? 1 : 0));
-  }
-
-  get magnitudeSquared() {
-    return this.reduce((total, q) => total += q ** 2, 0);
-  }
-
-  get magnitude() {
-    return Math.sqrt(this.magnitudeSquared);
-  }
-
-  scale(factor) {
-    return Vector.from(this.map((q) => q * factor));
-  }
-
-  normalize() {
-    return this.scale(1 / this.magnitude);
-  }
-
-  static randomUnitVector(totalDim) {
-    return Vector.from(Array(totalDim), () => Math.random()).normalize();
-  }
-
-  static zeros(totalDim) {
-    return Vector.from(Array(totalDim), () => 0);
-  }
-}
-
-export class Polygon {
-  constructor() {
-    this.vertices = [];
-    this.dim = 0;
-  }
-
-  addVertex(point) {
-    point = point instanceof Vector ? point : Vector.from(point);
-    if (!this.dim) {
-      this.dim = point.dim;
-    } else if (this.dim !== point.dim) {
-      throw new Error('All vertices of a polygon must have the same dimensionality');
-    }
-    this.vertices.push(point);
-  }
-}
-
-export class Rectangle extends Polygon {
-  constructor(startPoint, dimensions) {
-    super();
-    this.startPoint = Vector.from(startPoint);
-    this.dimensions = Vector.from(dimensions);
-    // Next point is obtained by moving the specified length along each dimension
-    // one at a time, then reversing these movements in the same order.
-    let point = this.startPoint;
-    for (let dim = dimensions.length - 1; dim >= 0; dim--) {
-      this.addVertex(point);
-      const increment = Vector.unitVector(dim, dimensions.length);
-      point = point.add(increment);
-    }
-    for (let dim = dimensions.length - 1; dim >= 0; dim--) {
-      this.addVertex(point);
-      const increment = Vector.unitVector(dim, dimensions.length);
-      point = point.subtract(increment);
-    }
-  }
-
-  get center() {
-    return Vector.from(this.dimensions.map((Q, idx) => this.startPoint[idx] + Q / 2));
-  }
-
-  doesOverlap(rect) {
-    return this.dimensions.every((_, idx) => {
-      const thisMin = this.startPoint[idx];
-      const thisMax = this.startPoint[idx] + this.dimensions[idx];
-      const thatMin = rect.startPoint[idx];
-      const thatMax = rect.startPoint[idx] + rect.dimensions[idx];
-      return (thisMin <= thatMin && thisMax >= thatMin)
-        || (thisMin >= thatMin && thisMin <= thatMax);
-    });
-  }
-}

src/classes/display/pairwise-forces.js

@@ -0,0 +1,35 @@
+import {
+  DEFAULT_OVERLAP_FORCE,
+  DEFAULT_TARGET_RADIUS,
+  DISTANCE_FACTOR,
+} from '../../util/constants.js';
+import { Rectangle, Vector } from '../supporting/geometry/index.js';
+
+const getRectangles = (boxes) => boxes.map((box) => (box instanceof Rectangle ? box : box.rect));
+const getCenters = (boxes) => getRectangles(boxes).map((rect) => rect.center);
+
+export const overlapRepulsionForce = (boxA, boxB, force = DEFAULT_OVERLAP_FORCE) => {
+  const [rectA, rectB] = getRectangles([boxA, boxB]);
+  const [centerA, centerB] = getCenters([rectA, rectB]);
+  const r = centerB.subtract(centerA);
+
+  // Apply a stronger force when overlap occurs
+  if (!rectA.doesOverlap(rectB)) {
+    return Vector.zeros(rectA.dim);
+  }
+  // If their centers actually coincide we can just randomize the direction.
+  if (r.magnitudeSquared === 0) {
+    return Vector.randomUnitVector(rectA.dim).scale(force);
+  }
+  return r.normalize().scale(force);
+};
+
+export const targetRadiusForce = (boxA, boxB, targetRadius = DEFAULT_TARGET_RADIUS) => {
+  const [centerA, centerB] = getCenters([boxA, boxB]);
+  const r = centerB.subtract(centerA);
+
+  // Repel if closer than targetRadius
+  // Attract if farther than targetRadius
+  const force = -DISTANCE_FACTOR * (r.magnitude - targetRadius);
+  return r.normalize().scale(force);
+};

src/classes/supporting/edge.js

@@ -46,7 +46,7 @@ export class Edge {
     }
     html += '</table>';
 
-    return `${Edge.getCombinedKey(this)}("${html}")`;
+    return html;
   }
 
   displayEdgeNode() {

src/classes/supporting/geometry/index.js

@@ -0,0 +1,3 @@
+export * from './vector.js';
+export * from './polygon.js';
+export * from './rectangle.js';

src/classes/supporting/geometry/polygon.js

@@ -0,0 +1,18 @@
+import { Vector } from './vector.js';
+
+export class Polygon {
+  constructor() {
+    this.vertices = [];
+    this.dim = 0;
+  }
+
+  addVertex(point) {
+    point = point instanceof Vector ? point : Vector.from(point);
+    if (!this.dim) {
+      this.dim = point.dim;
+    } else if (this.dim !== point.dim) {
+      throw new Error('All vertices of a polygon must have the same dimensionality');
+    }
+    this.vertices.push(point);
+  }
+}

src/classes/supporting/geometry/rectangle.js

@@ -0,0 +1,46 @@
+import { Polygon } from './polygon.js';
+import { Vector } from './vector.js';
+
+export class Rectangle extends Polygon {
+  constructor(position, dimensions) {
+    super();
+    if (this.vertices.length) {
+      throw new Error('Reinitializing geometry is not allowed');
+    }
+    this.position = Vector.from(position);
+    this.dimensions = Vector.from(dimensions);
+    // Next point is obtained by moving the specified length along each dimension
+    // one at a time, then reversing these movements in the same order.
+    let point = this.position;
+    for (let dim = dimensions.length - 1; dim >= 0; dim--) {
+      this.addVertex(point);
+      const increment = Vector.unitVector(dim, dimensions.length);
+      point = point.add(increment);
+    }
+    for (let dim = dimensions.length - 1; dim >= 0; dim--) {
+      this.addVertex(point);
+      const increment = Vector.unitVector(dim, dimensions.length);
+      point = point.subtract(increment);
+    }
+  }
+
+  get center() {
+    return Vector.from(this.dimensions.map((Q, idx) => this.position[idx] + Q / 2));
+  }
+
+  doesOverlap(rect) {
+    return this.dimensions.every((_, idx) => {
+      const thisMin = this.position[idx];
+      const thisMax = this.position[idx] + this.dimensions[idx];
+      const thatMin = rect.position[idx];
+      const thatMax = rect.position[idx] + rect.dimensions[idx];
+      return (thisMin <= thatMin && thisMax >= thatMin)
+        || (thisMin >= thatMin && thisMin <= thatMax);
+    });
+  }
+
+  get aspectRatio() {
+    const [width, height] = this.dimensions;
+    return height / width;
+  }
+}

src/classes/supporting/geometry/vector.js

@@ -0,0 +1,47 @@
+export class Vector extends Array {
+  get dim() {
+    return this.length ?? 0;
+  }
+
+  add(vector) {
+    if (vector.dim !== this.dim) {
+      throw new Error('Can only add vectors of the same dimensions');
+    }
+    return Vector.from(this.map((q, idx) => q + vector[idx]));
+  }
+
+  subtract(vector) {
+    if (vector.dim !== this.dim) {
+      throw new Error('Can only subtract vectors of the same dimensions');
+    }
+    return Vector.from(this.map((q, idx) => q - vector[idx]));
+  }
+
+  static unitVector(dim, totalDim) {
+    return Vector.from(Array(totalDim), (_, idx) => (idx === dim ? 1 : 0));
+  }
+
+  get magnitudeSquared() {
+    return this.reduce((total, q) => total += q ** 2, 0);
+  }
+
+  get magnitude() {
+    return Math.sqrt(this.magnitudeSquared);
+  }
+
+  scale(factor) {
+    return Vector.from(this.map((q) => q * factor));
+  }
+
+  normalize() {
+    return this.scale(1 / this.magnitude);
+  }
+
+  static randomUnitVector(totalDim) {
+    return Vector.from(Array(totalDim), () => Math.random()).normalize();
+  }
+
+  static zeros(totalDim) {
+    return Vector.from(Array(totalDim), () => 0);
+  }
+}

src/tests/scripts/force-directed.test.js

@@ -1,6 +1,7 @@
 import { Box } from '../../classes/display/box.js';
 import { ForceDirectedGraph } from '../../classes/display/force-directed.js';
-import { Rectangle, Vector } from '../../classes/display/geometry.js';
+import { Rectangle, Vector } from '../../classes/supporting/geometry/index.js';
+import { overlapRepulsionForce, targetRadiusForce } from '../../classes/display/pairwise-forces.js';
 import { delayOrWait } from '../../classes/display/scene-controls.js';
 import { Scene } from '../../classes/display/scene.js';
 import { EPSILON } from '../../util/constants.js';
@@ -31,13 +32,13 @@ describe('Force-Directed Graph', function tests() {
     rect.vertices[3].should.eql([1, 0]);
   });
 
-  it('overlapping boxes should repel with default force', () => {
+  it('overlapping boxes should repel', () => {
     const rect1 = new Rectangle([0, 0], [1, 1]);
     const rect2 = new Rectangle([0, 0], [1, 2]);
     rect1.center.should.eql([0.5, 0.5]);
     rect2.center.should.eql([0.5, 1]);
-    const force1 = ForceDirectedGraph.pairwiseForce(rect1, rect2, 10);
+    const force1 = overlapRepulsionForce(rect1, rect2, 10);
-    force1.should.eql([0, 200]);
+    force1.should.eql([0, 10]);
   });
 
   it('boxes at target radius should have no net force', () => {
@@ -45,7 +46,7 @@ describe('Force-Directed Graph', function tests() {
     const rect2 = new Rectangle([10, 0], [1, 1]);
     rect1.center.should.eql([0.5, 0.5]);
     rect2.center.should.eql([10.5, 0.5]);
-    const force = ForceDirectedGraph.pairwiseForce(rect1, rect2, 10);
+    const force = targetRadiusForce(rect1, rect2, 10);
     force[0].should.be.within(-EPSILON, EPSILON);
     force[1].should.be.within(-EPSILON, EPSILON);
   });
@@ -70,12 +71,14 @@ describe('Force-Directed Graph', function tests() {
     await delayOrWait(1000);
     const v = graph.addVertex('v1', 'box2');
     v.setProperty('prop', 'value');
-    await graph.runUntilEquilibrium();
   });
 
   it('can add an edge to the graph', async () => {
     await delayOrWait(1000);
     graph.addEdge('e1', 'box1', 'box2', 1);
+  });
+
+  it('runs until reaching equilibrium', async () => {
     await graph.runUntilEquilibrium();
   });
 });

src/util/constants.js

@@ -11,10 +11,12 @@ export const DEFAULT_OVERLAP_FORCE = 200;
 export const DEFAULT_REP_TOKEN_TYPE_ID = 0;
 export const DEFAULT_TARGET_RADIUS = 300;
 export const DEFAULT_TIME_STEP = 0.1;
-export const DISTANCE_FACTOR = 0.25;
+export const DISTANCE_FACTOR = 0.5;
 export const EPSILON = 2.23e-16;
 export const INCINERATOR_ADDRESS = '0';
+export const MAX_STEPS_TO_EQUILIBRIUM = 100;
 export const MINIMUM_FORCE = 1;
 export const MINIMUM_VELOCITY = 0.1;
 export const TIME_DILATION_FACTOR = 500;
+export const TRANSLATION_VELOCITY_FACTOR = 0.2;
 export const VISCOSITY_FACTOR = 0.4;