1 // Copyright 2014 The Rust Project Developers. See the COPYRIGHT
2 // file at the top-level directory of this distribution and at
3 // http://rust-lang.org/COPYRIGHT.
5 // Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
6 // http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
7 // <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
8 // option. This file may not be copied, modified, or distributed
9 // except according to those terms.
13 static PI: f64 = 3.141592653589793;
14 static SOLAR_MASS: f64 = 4.0 * PI * PI;
15 static YEAR: f64 = 365.24;
16 static N_BODIES: uint = 5;
18 static BODIES: [Planet, ..N_BODIES] = [
28 4.84143144246472090e+00,
29 -1.16032004402742839e+00,
30 -1.03622044471123109e-01,
33 1.66007664274403694e-03 * YEAR,
34 7.69901118419740425e-03 * YEAR,
35 -6.90460016972063023e-05 * YEAR,
37 mass: 9.54791938424326609e-04 * SOLAR_MASS,
42 8.34336671824457987e+00,
43 4.12479856412430479e+00,
44 -4.03523417114321381e-01,
47 -2.76742510726862411e-03 * YEAR,
48 4.99852801234917238e-03 * YEAR,
49 2.30417297573763929e-05 * YEAR,
51 mass: 2.85885980666130812e-04 * SOLAR_MASS,
56 1.28943695621391310e+01,
57 -1.51111514016986312e+01,
58 -2.23307578892655734e-01,
61 2.96460137564761618e-03 * YEAR,
62 2.37847173959480950e-03 * YEAR,
63 -2.96589568540237556e-05 * YEAR,
65 mass: 4.36624404335156298e-05 * SOLAR_MASS,
70 1.53796971148509165e+01,
71 -2.59193146099879641e+01,
72 1.79258772950371181e-01,
75 2.68067772490389322e-03 * YEAR,
76 1.62824170038242295e-03 * YEAR,
77 -9.51592254519715870e-05 * YEAR,
79 mass: 5.15138902046611451e-05 * SOLAR_MASS,
89 fn advance(bodies: &mut [Planet, ..N_BODIES], dt: f64, steps: i32) {
90 let mut d = [ 0.0, ..3 ];
91 for _ in range(0, steps) {
92 for i in range(0u, N_BODIES) {
93 for j in range(i + 1, N_BODIES) {
94 d[0] = bodies[i].x[0] - bodies[j].x[0];
95 d[1] = bodies[i].x[1] - bodies[j].x[1];
96 d[2] = bodies[i].x[2] - bodies[j].x[2];
98 let d2 = d[0]*d[0] + d[1]*d[1] + d[2]*d[2];
99 let mag = dt / (d2 * d2.sqrt());
101 let a_mass = bodies[i].mass;
102 let b_mass = bodies[j].mass;
103 bodies[i].v[0] -= d[0] * b_mass * mag;
104 bodies[i].v[1] -= d[1] * b_mass * mag;
105 bodies[i].v[2] -= d[2] * b_mass * mag;
107 bodies[j].v[0] += d[0] * a_mass * mag;
108 bodies[j].v[1] += d[1] * a_mass * mag;
109 bodies[j].v[2] += d[2] * a_mass * mag;
113 for a in bodies.mut_iter() {
114 a.x[0] += dt * a.v[0];
115 a.x[1] += dt * a.v[1];
116 a.x[2] += dt * a.v[2];
121 fn energy(bodies: &[Planet, ..N_BODIES]) -> f64 {
123 let mut d = [ 0.0, ..3 ];
124 for i in range(0u, N_BODIES) {
125 for k in range(0u, 3) {
126 e += bodies[i].mass * bodies[i].v[k] * bodies[i].v[k] / 2.0;
129 for j in range(i + 1, N_BODIES) {
130 for k in range(0u, 3) {
131 d[k] = bodies[i].x[k] - bodies[j].x[k];
133 let dist = (d[0]*d[0] + d[1]*d[1] + d[2]*d[2]).sqrt();
134 e -= bodies[i].mass * bodies[j].mass / dist;
140 fn offset_momentum(bodies: &mut [Planet, ..N_BODIES]) {
141 for i in range(0u, N_BODIES) {
142 for k in range(0u, 3) {
143 bodies[0].v[k] -= bodies[i].v[k] * bodies[i].mass / SOLAR_MASS;
149 let args = os::args();
150 let args = if os::getenv("RUST_BENCH").is_some() {
152 } else if args.len() <= 1u {
155 args.move_iter().collect()
158 let n: i32 = from_str::<i32>(*args.get(1)).unwrap();
159 let mut bodies = BODIES;
161 offset_momentum(&mut bodies);
162 println!("{:.9f}", energy(&bodies) as f64);
164 advance(&mut bodies, 0.01, n);
166 println!("{:.9f}", energy(&bodies) as f64);