ValaBench.vala

/* The Computer Language Benchmarks Game
   https://salsa.debian.org/benchmarksgame-team/benchmarksgame/

   contributed by Isaac Gouy 
*/

// using System;
[Compact]
class NBody {
   public static void main(string[] args) {        
      int n = 10000;
      print(@"sas $(args[1])\n");
      if (args.length > 0) n = int.parse(args[1]);
      print("get arg %d\n",n);

      NBodySystem bodies = new NBodySystem();

      print(@"$(bodies.Energy())\n");

      ulong microseconds;
	  double seconds;
      Timer timer = new Timer ();


      for (int i=0; i<n; i++) 
         bodies.Advance(0.01);

      timer.stop ();
      seconds = timer.elapsed (out microseconds);
	  print (@"sec = $seconds mcsec = $microseconds");
      print(@"$(bodies.Energy())\n");
   }
}


class NBodySystem {
   public Body[] bodies;
	   	  	
   public NBodySystem() {			
      bodies = new Body[]{
         Body.Sun(),		
         Body.Jupiter(),
         Body.Saturn(),
         Body.Uranus(),
         Body.Neptune()		      		      		      
      };
		
      double px = 0.0;
      double py = 0.0;	
      double pz = 0.0;				
      foreach (Body body in 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++) {
         Body bodyi = bodies[i];
         for (int j=i+1; j < bodies.length; j++) {	
            Body bodyj = bodies[j];

            dx = bodyi.x - bodyj.x;
            dy = bodyi.y - bodyj.y;
            dz = bodyi.z - bodyj.z;
				
            distance = Math.sqrt(dx*dx + dy*dy + dz*dz);				   
            mag = dt / (distance * distance * distance);
				
            bodyi.vx -= dx * bodyj.mass * mag;
            bodyi.vy -= dy * bodyj.mass * mag;
            bodyi.vz -= dz * bodyj.mass * mag;
				
            bodyj.vx += dx * bodyi.mass * mag;
            bodyj.vy += dy * bodyi.mass * mag;
            bodyj.vz += dz * bodyi.mass * mag;
         }
      }		
		
      foreach (Body body in 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++) {
         Body bodyi = bodies[i];

         e += 0.5 * bodyi.mass * 
            ( bodyi.vx * bodyi.vx 
            + bodyi.vy * bodyi.vy 
            + bodyi.vz * bodyi.vz );
			   
         for (int j=i+1; j < bodies.length; j++) {
            Body bodyj = bodies[j];

            dx = bodyi.x - bodyj.x;
            dy = bodyi.y - bodyj.y;
            dz = bodyi.z - bodyj.z;
				
            distance = Math.sqrt(dx*dx + dy*dy + dz*dz);
            e -= (bodyi.mass * bodyj.mass) / distance;
         }
      }
      return e;
   }		      	   	   	      	   		   														           		
}


class Body {
   const double PI = 3.141592653589793;	
   const double SOLAR_MASS = 4 * PI * PI;
   const double DAYS_PER_YEAR = 365.24;

   public double x;
   public double y;
   public double z;
   public double vx;
   public double vy;
   public double vz;
   public double mass;
   public Body(){}	
	
   internal static Body Jupiter() {
      Body p = new Body();
      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;
   }	
	
   internal static Body Saturn() {
      Body p = new Body();
      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;
   }	
	
   internal static Body Uranus() {
      Body p = new Body();
      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;
   }		

   internal static Body Neptune() {
      Body p = new Body();
      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;
   }
	
   internal static Body Sun() {
      Body p = new Body();
      p.mass = SOLAR_MASS;	   	   	   
      return p;
   }			
	
   internal Body OffsetMomentum(double px, double py, double pz) {
      vx = -px / SOLAR_MASS;
      vy = -py / SOLAR_MASS;
      vz = -pz / SOLAR_MASS;	   
      return this;   
   }			           			
}