public static Simulation initSpring(int count, double radius) {
Settings stt = new Settings();
stt.setTimeStep(1);
stt.setSpeedOfLight(3);
stt.setSimulationWidth(100);
stt.setSimulationHeight(100);
stt.addForce(new ConstantForce());
stt.addForce(new SpringForce());
stt.setNumOfParticles(count);
stt.setParticleRadius(radius);
stt.setParticleMaxSpeed(stt.getSpeedOfLight());
stt.setBoundary(GeneralBoundaryType.Periodic);
stt.setParticleSolver(new EulerRichardson());
for (int k = 0; k < count; k++) {
Particle par = new Particle();
par.setX(stt.getSimulationWidth() * Math.random());
par.setY(stt.getSimulationHeight() * Math.random());
par.setRadius(15);
par.setVx(10 * Math.random());
par.setVy(0);
par.setMass(1);
par.setCharge(.001);
stt.addParticle(par);
}
Simulation simulation = new Simulation(stt);
return simulation;
}
/**
* Creates particles on random positions with random speeds
*
* @param width maximal x-coodrinate
* @param height maximal y-coordinate
* @param maxspeed maximal particle speed
* @param count number of particles to be created
* @param radius particle radius
* @return ArrayList of Particle2D
*/
public static ArrayList<Particle> createRandomParticles(
double width, double height, double maxspeed, int count, double radius) {
ArrayList<Particle> particlelist = new ArrayList<Particle>(count);
for (int k = 0; k < count; k++) {
Particle p = new Particle();
p.setX(width * Math.random());
p.setY(height * Math.random());
p.setRadius(radius);
phi = 2 * Math.PI * Math.random();
p.setVx(maxspeed * Math.cos(phi));
p.setVy(maxspeed * Math.sin(phi));
p.setMass(1);
if (Math.random() > 0.5) {
p.setCharge(.1);
} else {
p.setCharge(-.1);
}
particlelist.add(p);
}
return particlelist;
}