tor-browser

The Tor Browser
git clone https://git.dasho.dev/tor-browser.git
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check-access-nbody.js (4188B)

      1 /* The Great Computer Language Shootout
      2   http://shootout.alioth.debian.org/
      3   contributed by Isaac Gouy */
      4 
      5 var PI = 3.141592653589793;
      6 var SOLAR_MASS = 4 * PI * PI;
      7 var DAYS_PER_YEAR = 365.24;
      8 
      9 function Body(x,y,z,vx,vy,vz,mass){
     10   this.x = x;
     11   this.y = y;
     12   this.z = z;
     13   this.vx = vx;
     14   this.vy = vy;
     15   this.vz = vz;
     16   this.mass = mass;
     17 }
     18 
     19 Body.prototype.offsetMomentum = function(px,py,pz) {
     20   this.vx = -px / SOLAR_MASS;
     21   this.vy = -py / SOLAR_MASS;
     22   this.vz = -pz / SOLAR_MASS;
     23   return this;
     24 }
     25 
     26 function Jupiter(){
     27   return new Body(
     28      4.84143144246472090e+00,
     29      -1.16032004402742839e+00,
     30      -1.03622044471123109e-01,
     31      1.66007664274403694e-03 * DAYS_PER_YEAR,
     32      7.69901118419740425e-03 * DAYS_PER_YEAR,
     33      -6.90460016972063023e-05 * DAYS_PER_YEAR,
     34      9.54791938424326609e-04 * SOLAR_MASS
     35   );
     36 }
     37 
     38 function Saturn(){
     39   return new Body(
     40      8.34336671824457987e+00,
     41      4.12479856412430479e+00,
     42      -4.03523417114321381e-01,
     43      -2.76742510726862411e-03 * DAYS_PER_YEAR,
     44      4.99852801234917238e-03 * DAYS_PER_YEAR,
     45      2.30417297573763929e-05 * DAYS_PER_YEAR,
     46      2.85885980666130812e-04 * SOLAR_MASS
     47   );
     48 }
     49 
     50 function Uranus(){
     51   return new Body(
     52      1.28943695621391310e+01,
     53      -1.51111514016986312e+01,
     54      -2.23307578892655734e-01,
     55      2.96460137564761618e-03 * DAYS_PER_YEAR,
     56      2.37847173959480950e-03 * DAYS_PER_YEAR,
     57      -2.96589568540237556e-05 * DAYS_PER_YEAR,
     58      4.36624404335156298e-05 * SOLAR_MASS
     59   );
     60 }
     61 
     62 function Neptune(){
     63   return new Body(
     64      1.53796971148509165e+01,
     65      -2.59193146099879641e+01,
     66      1.79258772950371181e-01,
     67      2.68067772490389322e-03 * DAYS_PER_YEAR,
     68      1.62824170038242295e-03 * DAYS_PER_YEAR,
     69      -9.51592254519715870e-05 * DAYS_PER_YEAR,
     70      5.15138902046611451e-05 * SOLAR_MASS
     71   );
     72 }
     73 
     74 function Sun(){
     75   return new Body(0.0, 0.0, 0.0, 0.0, 0.0, 0.0, SOLAR_MASS);
     76 }
     77 
     78 
     79 function NBodySystem(bodies){
     80   this.bodies = bodies;
     81   var px = 0.0;
     82   var py = 0.0;
     83   var pz = 0.0;
     84   var size = this.bodies.length;
     85   for (var i=0; i<size; i++){
     86      var b = this.bodies[i];
     87      var m = b.mass;
     88      px += b.vx * m;
     89      py += b.vy * m;
     90      pz += b.vz * m;
     91   }
     92   this.bodies[0].offsetMomentum(px,py,pz);
     93 }
     94 
     95 NBodySystem.prototype.advance = function(dt){
     96   var dx, dy, dz, distance, mag;
     97   var size = this.bodies.length;
     98 
     99   for (var i=0; i<size; i++) {
    100      var bodyi = this.bodies[i];
    101      for (var j=i+1; j<size; j++) {
    102         var bodyj = this.bodies[j];
    103         dx = bodyi.x - bodyj.x;
    104         dy = bodyi.y - bodyj.y;
    105         dz = bodyi.z - bodyj.z;
    106 
    107         distance = Math.sqrt(dx*dx + dy*dy + dz*dz);
    108         mag = dt / (distance * distance * distance);
    109 
    110         bodyi.vx -= dx * bodyj.mass * mag;
    111         bodyi.vy -= dy * bodyj.mass * mag;
    112         bodyi.vz -= dz * bodyj.mass * mag;
    113 
    114         bodyj.vx += dx * bodyi.mass * mag;
    115         bodyj.vy += dy * bodyi.mass * mag;
    116         bodyj.vz += dz * bodyi.mass * mag;
    117      }
    118   }
    119 
    120   for (var i=0; i<size; i++) {
    121      var body = this.bodies[i];
    122      body.x += dt * body.vx;
    123      body.y += dt * body.vy;
    124      body.z += dt * body.vz;
    125   }
    126 }
    127 
    128 NBodySystem.prototype.energy = function(){
    129   var dx, dy, dz, distance;
    130   var e = 0.0;
    131   var size = this.bodies.length;
    132 
    133   for (var i=0; i<size; i++) {
    134      var bodyi = this.bodies[i];
    135 
    136      e += 0.5 * bodyi.mass *
    137         ( bodyi.vx * bodyi.vx
    138         + bodyi.vy * bodyi.vy
    139         + bodyi.vz * bodyi.vz );
    140 
    141      for (var j=i+1; j<size; j++) {
    142         var bodyj = this.bodies[j];
    143         dx = bodyi.x - bodyj.x;
    144         dy = bodyi.y - bodyj.y;
    145         dz = bodyi.z - bodyj.z;
    146 
    147         distance = Math.sqrt(dx*dx + dy*dy + dz*dz);
    148         e -= (bodyi.mass * bodyj.mass) / distance;
    149      }
    150   }
    151   return e;
    152 }
    153 
    154 var ret;
    155 
    156 for ( var n = 3; n <= 24; n *= 2 ) {
    157    (function(){
    158        var bodies = new NBodySystem( Array(
    159           Sun(),Jupiter(),Saturn(),Uranus(),Neptune()
    160        ));
    161        var max = n * 100;
    162        
    163        ret = bodies.energy();
    164        for (var i=0; i<max; i++){
    165            bodies.advance(0.01);
    166        }
    167        ret = bodies.energy();
    168    })();
    169 }
    170 
    171 assertEq(ret, -0.16906933525822856)