/* The Computer Language Benchmarks Gamehttps://salsa.debian.org/benchmarksgame-team/benchmarksgame/contributed by Mark C. Lewis*/import java.text.NumberFormat;final class Nbody2 {private final Body2[] bodies;public Nbody2() {bodies = new Body2[]{Body2.sun(), Body2.jupiter(), Body2.saturn(), Body2.uranus(), Body2.neptune()};double px = 0.0;double py = 0.0;double pz = 0.0;for (Body2 body : bodies) {px += body.vx * body.mass;py += body.vy * body.mass;pz += body.vz * body.mass;}bodies[0].offsetMomentum(px, py, pz);}public void advance(double dt) {double dx, dy, dz, distance, mag;for (int i = 0; i < bodies.length; ++i) {for (int j = i + 1; j < bodies.length; ++j) {dx = bodies[i].x - bodies[j].x;dy = bodies[i].y - bodies[j].y;dz = bodies[i].z - bodies[j].z;distance = Math.sqrt(dx * dx + dy * dy + dz * dz);mag = dt / (distance * distance * distance);bodies[i].vx -= dx * bodies[j].mass * mag;bodies[i].vy -= dy * bodies[j].mass * mag;bodies[i].vz -= dz * bodies[j].mass * mag;bodies[j].vx += dx * bodies[i].mass * mag;bodies[j].vy += dy * bodies[i].mass * mag;bodies[j].vz += dz * bodies[i].mass * mag;}}for (Body2 body : bodies) {body.x += dt * body.vx;body.y += dt * body.vy;body.z += dt * body.vz;}}public double energy() {double dx, dy, dz, distance;double e = 0.0;for (int i = 0; i < bodies.length; ++i) {e += 0.5* bodies[i].mass* (bodies[i].vx * bodies[i].vx+ bodies[i].vy * bodies[i].vy+ bodies[i].vz * bodies[i].vz);for (int j = i + 1; j < bodies.length; ++j) {dx = bodies[i].x - bodies[j].x;dy = bodies[i].y - bodies[j].y;dz = bodies[i].z - bodies[j].z;distance = Math.sqrt(dx * dx + dy * dy + dz * dz);e -= (bodies[i].mass * bodies[j].mass) / distance;}}return e;}public static void main(String[] args) {NumberFormat nf = NumberFormat.getInstance();nf.setMaximumFractionDigits(9);nf.setMinimumFractionDigits(9);nf.setGroupingUsed(false);int n = Integer.parseInt(args[0]);Nbody2 bodies = new Nbody2();System.out.println(nf.format(bodies.energy()));for (int i = 0; i < n; ++i) {bodies.advance(0.01);}System.out.println(nf.format(bodies.energy()));}}final class Body2 {static final double PI = 3.141592653589793;static final double SOLAR_MASS = 4 * PI * PI;static final double DAYS_PER_YEAR = 365.24;public double x, y, z, vx, vy, vz, mass;public Body2() {}static Body2 jupiter() {Body2 p = new Body2();p.x = 4.84143144246472090e+00;p.y = -1.16032004402742839e+00;p.z = -1.03622044471123109e-01;p.vx = 1.66007664274403694e-03 * DAYS_PER_YEAR;p.vy = 7.69901118419740425e-03 * DAYS_PER_YEAR;p.vz = -6.90460016972063023e-05 * DAYS_PER_YEAR;p.mass = 9.54791938424326609e-04 * SOLAR_MASS;return p;}static Body2 saturn() {Body2 p = new Body2();p.x = 8.34336671824457987e+00;p.y = 4.12479856412430479e+00;p.z = -4.03523417114321381e-01;p.vx = -2.76742510726862411e-03 * DAYS_PER_YEAR;p.vy = 4.99852801234917238e-03 * DAYS_PER_YEAR;p.vz = 2.30417297573763929e-05 * DAYS_PER_YEAR;p.mass = 2.85885980666130812e-04 * SOLAR_MASS;return p;}static Body2 uranus() {Body2 p = new Body2();p.x = 1.28943695621391310e+01;p.y = -1.51111514016986312e+01;p.z = -2.23307578892655734e-01;p.vx = 2.96460137564761618e-03 * DAYS_PER_YEAR;p.vy = 2.37847173959480950e-03 * DAYS_PER_YEAR;p.vz = -2.96589568540237556e-05 * DAYS_PER_YEAR;p.mass = 4.36624404335156298e-05 * SOLAR_MASS;return p;}static Body2 neptune() {Body2 p = new Body2();p.x = 1.53796971148509165e+01;p.y = -2.59193146099879641e+01;p.z = 1.79258772950371181e-01;p.vx = 2.68067772490389322e-03 * DAYS_PER_YEAR;p.vy = 1.62824170038242295e-03 * DAYS_PER_YEAR;p.vz = -9.51592254519715870e-05 * DAYS_PER_YEAR;p.mass = 5.15138902046611451e-05 * SOLAR_MASS;return p;}static Body2 sun() {Body2 p = new Body2();p.mass = SOLAR_MASS;return p;}void offsetMomentum(double px, double py, double pz) {vx = -px / SOLAR_MASS;vy = -py / SOLAR_MASS;vz = -pz / SOLAR_MASS;}}
此处可能存在不合适展示的内容,页面不予展示。您可通过相关编辑功能自查并修改。
如您确认内容无涉及 不当用语 / 纯广告导流 / 暴力 / 低俗色情 / 侵权 / 盗版 / 虚假 / 无价值内容或违法国家有关法律法规的内容,可点击提交进行申诉,我们将尽快为您处理。