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A few updates based on code review by amcameron

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This commit is contained in:
Dennis Hotson 2011-08-15 16:52:18 +10:00
parent 376e116714
commit b791fafe9a
1 changed files with 7 additions and 11 deletions
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18
springy.js
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@ -305,10 +305,7 @@ Layout.ForceDirected.prototype.applyCoulombsLaw = function() {
if (point1 !== point2) if (point1 !== point2)
{ {
var d = point1.p.subtract(point2.p); var d = point1.p.subtract(point2.p);
// Why is distance = mag + 1.0? If there's a good reason for var distance = d.magnitude();
// it, leave a comment. Is it to keep the repulsion from being
// way too strong at small distances?
var distance = d.magnitude() + 1.0;
var direction = d.normalise(); var direction = d.normalise();
// apply force to each end point // apply force to each end point
@ -343,8 +340,8 @@ Layout.ForceDirected.prototype.updateVelocity = function(timestep) {
this.eachNode(function(node, point) { this.eachNode(function(node, point) {
// Is this, along with updatePosition below, the only places that your // Is this, along with updatePosition below, the only places that your
// integration code exist? // integration code exist?
point.v = point.v.add(point.f.multiply(timestep)).multiply(this.damping); point.v = point.v.add(point.a.multiply(timestep)).multiply(this.damping);
point.f = new Vector(0,0); point.a = new Vector(0,0);
}); });
}; };
@ -356,13 +353,12 @@ Layout.ForceDirected.prototype.updatePosition = function(timestep) {
}); });
}; };
// Calculate the total kinetic energy of the system
Layout.ForceDirected.prototype.totalEnergy = function(timestep) { Layout.ForceDirected.prototype.totalEnergy = function(timestep) {
var energy = 0.0; var energy = 0.0;
this.eachNode(function(node, point) { this.eachNode(function(node, point) {
var speed = point.v.magnitude(); var speed = point.v.magnitude();
// A comment might be warranted explaining why the factor of 1/2 is energy += 0.5 * point.m * speed * speed;
// unnecessary.
energy += speed * speed;
}); });
return energy; return energy;
@ -494,12 +490,12 @@ Layout.ForceDirected.Point = function(position, mass) {
this.v = new Vector(0, 0); // velocity this.v = new Vector(0, 0); // velocity
// Based on the usage, the "force" member looks more like an // Based on the usage, the "force" member looks more like an
// "acceleration". // "acceleration".
this.f = new Vector(0, 0); // force this.a = new Vector(0, 0); // force
}; };
Layout.ForceDirected.Point.prototype.applyForce = function(force) { Layout.ForceDirected.Point.prototype.applyForce = function(force) {
// Ditto on acceleration, here: a = F/m // Ditto on acceleration, here: a = F/m
this.f = this.f.add(force.divide(this.m)); this.a = this.a.add(force.divide(this.m));
}; };
// Spring // Spring