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import "allocator/arena";
// From The Computer Language Benchmarks Game
// http://benchmarksgame.alioth.debian.org
type float = f64; // interchangeable f32/f64 for testing
const SOLAR_MASS = <float>(4.0 * Math.PI * Math.PI);
const DAYS_PER_YEAR: float = 365.24;
class Body {
constructor(
public x: float,
public y: float,
public z: float,
public vx: float,
public vy: float,
public vz: float,
public mass: float
) {}
offsetMomentum(px: float, py: float, pz: float): this {
this.vx = -px / SOLAR_MASS;
this.vy = -py / SOLAR_MASS;
this.vz = -pz / SOLAR_MASS;
return this;
}
}
function Sun(): Body {
return new Body(
0.0, 0.0, 0.0, 0.0, 0.0, 0.0, SOLAR_MASS
);
}
function Jupiter(): Body {
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(): Body {
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(): Body {
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(): Body {
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(public bodies: Body[]) {
var px: float = 0.0;
var py: float = 0.0;
var pz: float = 0.0;
var size = bodies.length;
for (let i = 0; i < size; ++i) {
let b = unchecked(bodies[i]);
let m = b.mass;
px += b.vx * m;
py += b.vy * m;
pz += b.vz * m;
}
bodies[0].offsetMomentum(px, py, pz);
}
advance(dt: float): void {
var bodies = this.bodies;
var size: u32 = bodies.length;
// var buffer = changetype<usize>(bodies.buffer_);
for (let i: u32 = 0; i < size; ++i) {
let bodyi = unchecked(bodies[i]);
// let bodyi = load<Body>(buffer + i * sizeof<Body>(), 8);
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: u32 = i + 1; j < size; ++j) {
let bodyj = unchecked(bodies[j]);
// let bodyj = load<Body>(buffer + j * sizeof<Body>(), 8);
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 = <float>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(): float {
var e: float = 0.0;
var bodies = this.bodies;
for (let i: u32 = 0, size: u32 = bodies.length; i < size; ++i) {
let bodyi = unchecked(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: u32 = i + 1; j < size; ++j) {
let bodyj = unchecked(bodies[j]);
let dx = ix - bodyj.x;
let dy = iy - bodyj.y;
let dz = iz - bodyj.z;
let distance = <float>Math.sqrt(dx * dx + dy * dy + dz * dz);
e -= bim * bodyj.mass / distance;
}
}
return e;
}
}
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var system: NBodySystem;
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export function init(): void {
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system = new NBodySystem([
Sun(),
Jupiter(),
Saturn(),
Uranus(),
Neptune()
]);
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}
export function step(): float {
system.advance(0.01);
return system.energy();
}
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export function bench(steps: u32): void {
for (let i: u32 = 0; i < steps; ++i) system.advance(0.01);
}
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export function getBody(index: i32): Body | null {
var bodies = system.bodies;
return <u32>index < <u32>bodies.length ? bodies[index] : null;
}