User:Positive/Optimal Velocity

To not clutter up the Talk:Robocode/Game Physics page:

I believe this is the correct getClosestReachableVelocityToVelocity function (feel free to comment):

double getClosestReachableVelocityToVelocity(double currentVelocity,double wantedVelocity)
{
 // this function assumes wantedVelocity<=Rules.MAXVELOCITY
 // with this function you can basically assume setAhead(Infinity) or setAhead(-Infinity)
 // was called, and you determine the next velocity based on the max velocity
 // set by the robot. For example, if the current velocity is 0 and the max velocity
 // set was 4.0, it would return 1.0. If the current velocity was 8.0, it would return 6.0.
 if(wantedVelocity<0)
  return -getClosestReachableVelocityToVelocity(-currentVelocity,-wantedVelocity);
 if(currentVelocity<0)
 {
  double nextVelocity;
  // we are travelling the wrong way, decelerate
  nextVelocity = currentVelocity + Rules.DECELERATION;
  if(nextVelocity>Rules.ACCELERATION)
   // make sure we can't jump from -0.1 to 1.9 or something
   nextVelocity = Rules.ACCELERATION;
  if(nextVelocity>wantedVelocity)
   // if the wanted velocity is for example 0.5, limit the velocity to that.
   return wantedVelocity;
  else
   // else return the highest possible
   return nextVelocity;
 }
 else
 {
  if(currentVelocity>wantedVelocity)
  {
   // both velocities are positive, but we need to decelerate
   double nextVelocity = currentVelocity - Rules.DECELERATION;
   if(nextVelocity<wantedVelocity)
    // if we can decelerate more than what's wanted, return what's wanted
    return wantedVelocity;
   else
    // else return the closest to it
    return nextVelocity;
  }
  else
  {
   // the wantedVelocity is higher than current
   double nextVelocity = currentVelocity + Rules.ACCELERATION;
   if(nextVelocity>wantedVelocity)
    // if we can accelerate more than what's wanted, return what's wanted
    return wantedVelocity;
   else
    // else return the closest to it
    return nextVelocity;
  }
 }
}