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.
11 static PI: f64 = 3.141592653589793;
12 static SOLAR_MASS: f64 = 4.0 * PI * PI;
13 static YEAR: f64 = 365.24;
14 static N_BODIES: uint = 5;
16 static BODIES: [Planet, ..N_BODIES] = [
19 x: 0.0, y: 0.0, z: 0.0,
20 vx: 0.0, vy: 0.0, vz: 0.0,
25 x: 4.84143144246472090e+00,
26 y: -1.16032004402742839e+00,
27 z: -1.03622044471123109e-01,
28 vx: 1.66007664274403694e-03 * YEAR,
29 vy: 7.69901118419740425e-03 * YEAR,
30 vz: -6.90460016972063023e-05 * YEAR,
31 mass: 9.54791938424326609e-04 * SOLAR_MASS,
35 x: 8.34336671824457987e+00,
36 y: 4.12479856412430479e+00,
37 z: -4.03523417114321381e-01,
38 vx: -2.76742510726862411e-03 * YEAR,
39 vy: 4.99852801234917238e-03 * YEAR,
40 vz: 2.30417297573763929e-05 * YEAR,
41 mass: 2.85885980666130812e-04 * SOLAR_MASS,
45 x: 1.28943695621391310e+01,
46 y: -1.51111514016986312e+01,
47 z: -2.23307578892655734e-01,
48 vx: 2.96460137564761618e-03 * YEAR,
49 vy: 2.37847173959480950e-03 * YEAR,
50 vz: -2.96589568540237556e-05 * YEAR,
51 mass: 4.36624404335156298e-05 * SOLAR_MASS,
55 x: 1.53796971148509165e+01,
56 y: -2.59193146099879641e+01,
57 z: 1.79258772950371181e-01,
58 vx: 2.68067772490389322e-03 * YEAR,
59 vy: 1.62824170038242295e-03 * YEAR,
60 vz: -9.51592254519715870e-05 * YEAR,
61 mass: 5.15138902046611451e-05 * SOLAR_MASS,
66 x: f64, y: f64, z: f64,
67 vx: f64, vy: f64, vz: f64,
71 fn advance(bodies: &mut [Planet, ..N_BODIES], dt: f64, steps: int) {
72 for _ in range(0, steps) {
73 let mut b_slice = bodies.as_mut_slice();
75 let bi = match b_slice.mut_shift_ref() {
79 for bj in b_slice.mut_iter() {
84 let d2 = dx * dx + dy * dy + dz * dz;
85 let mag = dt / (d2 * d2.sqrt());
87 let massj_mag = bj.mass * mag;
88 bi.vx -= dx * massj_mag;
89 bi.vy -= dy * massj_mag;
90 bi.vz -= dz * massj_mag;
92 let massi_mag = bi.mass * mag;
93 bj.vx += dx * massi_mag;
94 bj.vy += dy * massi_mag;
95 bj.vz += dz * massi_mag;
104 fn energy(bodies: &[Planet, ..N_BODIES]) -> f64 {
106 let mut bodies = bodies.as_slice();
108 let bi = match bodies.shift_ref() {
112 e += (bi.vx * bi.vx + bi.vy * bi.vy + bi.vz * bi.vz) * bi.mass / 2.0;
113 for bj in bodies.iter() {
114 let dx = bi.x - bj.x;
115 let dy = bi.y - bj.y;
116 let dz = bi.z - bj.z;
117 let dist = (dx * dx + dy * dy + dz * dz).sqrt();
118 e -= bi.mass * bj.mass / dist;
124 fn offset_momentum(bodies: &mut [Planet, ..N_BODIES]) {
128 for bi in bodies.iter() {
129 px += bi.vx * bi.mass;
130 py += bi.vy * bi.mass;
131 pz += bi.vz * bi.mass;
133 let sun = &mut bodies[0];
134 sun.vx = - px / SOLAR_MASS;
135 sun.vy = - py / SOLAR_MASS;
136 sun.vz = - pz / SOLAR_MASS;
140 let n = if std::os::getenv("RUST_BENCH").is_some() {
143 std::os::args().as_slice().get(1)
144 .and_then(|arg| from_str(arg.as_slice()))
147 let mut bodies = BODIES;
149 offset_momentum(&mut bodies);
150 println!("{:.9f}", energy(&bodies));
152 advance(&mut bodies, 0.01, n);
154 println!("{:.9f}", energy(&bodies));