Compare n-body to asmjs and js

examples/n-body/build/index.js

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+"use strict";
+Object.defineProperty(exports, "__esModule", { value: true });
+require("allocator/arena");
+const SOLAR_MASS = 4.0 * Math.PI * Math.PI;
+const DAYS_PER_YEAR = 365.24;
+class Body {
+    constructor(x, y, z, vx, vy, vz, mass) {
+        this.x = x;
+        this.y = y;
+        this.z = z;
+        this.vx = vx;
+        this.vy = vy;
+        this.vz = vz;
+        this.mass = mass;
+    }
+    offsetMomentum(px, py, pz) {
+        this.vx = -px / SOLAR_MASS;
+        this.vy = -py / SOLAR_MASS;
+        this.vz = -pz / SOLAR_MASS;
+        return this;
+    }
+}
+function Sun() {
+    return new Body(0.0, 0.0, 0.0, 0.0, 0.0, 0.0, SOLAR_MASS);
+}
+function Jupiter() {
+    return new Body(4.84143144246472090e+00, -1.16032004402742839e+00, -1.03622044471123109e-01, 1.66007664274403694e-03 * DAYS_PER_YEAR, 7.69901118419740425e-03 * DAYS_PER_YEAR, -6.90460016972063023e-05 * DAYS_PER_YEAR, 9.54791938424326609e-04 * SOLAR_MASS);
+}
+function Saturn() {
+    return new Body(8.34336671824457987e+00, 4.12479856412430479e+00, -4.03523417114321381e-01, -2.76742510726862411e-03 * DAYS_PER_YEAR, 4.99852801234917238e-03 * DAYS_PER_YEAR, 2.30417297573763929e-05 * DAYS_PER_YEAR, 2.85885980666130812e-04 * SOLAR_MASS);
+}
+function Uranus() {
+    return new Body(1.28943695621391310e+01, -1.51111514016986312e+01, -2.23307578892655734e-01, 2.96460137564761618e-03 * DAYS_PER_YEAR, 2.37847173959480950e-03 * DAYS_PER_YEAR, -2.96589568540237556e-05 * DAYS_PER_YEAR, 4.36624404335156298e-05 * SOLAR_MASS);
+}
+function Neptune() {
+    return new Body(1.53796971148509165e+01, -2.59193146099879641e+01, 1.79258772950371181e-01, 2.68067772490389322e-03 * DAYS_PER_YEAR, 1.62824170038242295e-03 * DAYS_PER_YEAR, -9.51592254519715870e-05 * DAYS_PER_YEAR, 5.15138902046611451e-05 * SOLAR_MASS);
+}
+class NBodySystem {
+    constructor(bodies) {
+        var px = 0.0;
+        var py = 0.0;
+        var pz = 0.0;
+        var size = bodies.length;
+        for (let i = 0; i < size; i++) {
+            let b = bodies[i];
+            let m = b.mass;
+            px += b.vx * m;
+            py += b.vy * m;
+            pz += b.vz * m;
+        }
+        this.bodies = bodies;
+        this.bodies[0].offsetMomentum(px, py, pz);
+    }
+    advance(dt) {
+        var bodies = this.bodies;
+        var size = bodies.length;
+        for (let i = 0; i < size; ++i) {
+            let bodyi = bodies[i];
+            let ix = bodyi.x;
+            let iy = bodyi.y;
+            let iz = bodyi.z;
+            let bivx = bodyi.vx;
+            let bivy = bodyi.vy;
+            let bivz = bodyi.vz;
+            let bodyim = bodyi.mass;
+            for (let j = i + 1; j < size; ++j) {
+                let bodyj = bodies[j];
+                let dx = ix - bodyj.x;
+                let dy = iy - bodyj.y;
+                let dz = iz - bodyj.z;
+                let distanceSq = dx * dx + dy * dy + dz * dz;
+                let distance = Math.sqrt(distanceSq);
+                let mag = dt / (distanceSq * distance);
+                let bim = bodyim * mag;
+                let bjm = bodyj.mass * mag;
+                bivx -= dx * bjm;
+                bivy -= dy * bjm;
+                bivz -= dz * bjm;
+                bodyj.vx += dx * bim;
+                bodyj.vy += dy * bim;
+                bodyj.vz += dz * bim;
+            }
+            bodyi.vx = bivx;
+            bodyi.vy = bivy;
+            bodyi.vz = bivz;
+            bodyi.x += dt * bivx;
+            bodyi.y += dt * bivy;
+            bodyi.z += dt * bivz;
+        }
+    }
+    energy() {
+        var e = 0.0;
+        var bodies = this.bodies;
+        var size = bodies.length;
+        for (let i = 0; i < size; ++i) {
+            let bodyi = bodies[i];
+            let ix = bodyi.x;
+            let iy = bodyi.y;
+            let iz = bodyi.z;
+            let vx = bodyi.vx;
+            let vy = bodyi.vy;
+            let vz = bodyi.vz;
+            let bim = bodyi.mass;
+            e += 0.5 * bim * (vx * vx + vy * vy + vz * vz);
+            for (let j = i + 1; j < size; ++j) {
+                let bodyj = bodies[j];
+                let dx = ix - bodyj.x;
+                let dy = iy - bodyj.y;
+                let dz = iz - bodyj.z;
+                let distance = Math.sqrt(dx * dx + dy * dy + dz * dz);
+                e -= bim * bodyj.mass / distance;
+            }
+        }
+        return e;
+    }
+}
+var system;
+function init() {
+    var bodies = new Array();
+    bodies.push(Sun());
+    bodies.push(Jupiter());
+    bodies.push(Saturn());
+    bodies.push(Uranus());
+    bodies.push(Neptune());
+    system = new NBodySystem(bodies);
+}
+exports.init = init;
+function getBody(index) {
+    var bodies = system.bodies;
+    return index < bodies.length ? bodies[index] : null;
+}
+exports.getBody = getBody;
+function step() {
+    system.advance(0.01);
+    return system.energy();
+}
+exports.step = step;
+function bench(steps) {
+    for (let i = 0; i < steps; i++)
+        system.advance(0.01);
+}
+exports.bench = bench;