/*
  * The magnetic potential of an atom is always zero, because magnetic force does not do any work. But for a dipole
  * moment, it is not zero.
  *
  * FIXME: I didn't find a closed-form solution for an electric dipole's magnetic potential.
  */
 double getPotential(Particle p, float time) {
   if (bounds != null && !bounds.contains(p.getRx(), p.getRy())) return 0;
   double poten = 0.0;
   if (p instanceof GayBerneParticle) {
     GayBerneParticle gb = (GayBerneParticle) p;
     if (Math.abs(gb.dipoleMoment) > 0) {
       double temp = Math.sin(gb.theta) * gb.vx - Math.cos(gb.theta) * gb.vy;
       if (o == OUTWARD) temp = -temp;
       poten = gb.dipoleMoment * b * temp;
     }
   }
   return poten;
 }
 void dyn(Particle p) {
   if (bounds != null && !bounds.contains(p.getRx(), p.getRy())) return;
   double temp = Math.abs(b) * p.charge * MDModel.GF_CONVERSION_CONSTANT / p.getMass();
   if (o == OUTWARD) temp = -temp;
   p.fx += temp * p.vy;
   p.fy -= temp * p.vx;
   if (p instanceof GayBerneParticle) {
     GayBerneParticle gb = (GayBerneParticle) p;
     if (Math.abs(gb.dipoleMoment) > 0) {
       temp = Math.cos(gb.theta) * gb.vx + Math.sin(gb.theta) * gb.vy;
       if (o == OUTWARD) temp = -temp;
       gb.tau -= gb.dipoleMoment * temp * b / gb.inertia * MDModel.GF_CONVERSION_CONSTANT;
     }
   }
 }