/// <summary>
/// The position of the third (and follwing) primary particle is determined by the PCA:
/// The radius determined by the geometrical properties is computed and the
/// primary particle is positioned in that distance to the existing ones.
/// If that primary particle is in contact with another one but not
/// overlapping with any other, it may reside there.
/// </summary>
/// <param name="primaryParticles"></param>
/// <param name="count"></param>
/// <returns></returns>
public bool AddNextPrimaryParticle(List <PrimaryParticle> primaryParticles, int count, INeighborslist neighborslist)
{
var com = primaryParticles.GetCenterOfMass();
// compute the distance for the next primary particle to fulfill fractal dimension
var ppDistance = GetNextPrimaryParticleDistance(primaryParticles);
// get a new primary particle without any position yet.
var particle = InitializeNewPrimaryParticle(_psd.GetRandomSize());
var found = false;
var rndPosition = new Vector3();
while (!found)
{
// get a new random position on the sphere of allowed positions
rndPosition = ParticleFormationUtil.GetRandomPosition(_rndGen, ppDistance) + com;
// check if that position is valid
found = IsPrimaryParticlePositionValid(particle, rndPosition, neighborslist, primaryParticles, _config);
if (count > _config.MaxAttemptsPerCluster)
{
_logger.Debug("Resetting cluster generation. Time limit exceeded.");
return(false);
}
count++;
}
particle.MoveTo(rndPosition);
primaryParticles.Add(particle);
neighborslist.AddParticlesToNeighborsList(particle);
return(true);
}
/// <summary>
/// The second primary particle position is determined by its and the radius of the initial primary particle
/// </summary>
/// <param name="primaryParticles"></param>
public void SetSecondPrimaryParticle(List <PrimaryParticle> primaryParticles)
{
var radius = _psd.GetRandomSize();
// Distance of the CenterOfMass (com) of the second pp from the com
// of the first pp
var particle = new PrimaryParticle(0, radius);
// Position the second primary particle directly in contact with the first
var ppDistance = _config.Epsilon * (primaryParticles[0].Radius + particle.Radius);
// Get any random position withon that distance
var rndPosition = ParticleFormationUtil.GetRandomPosition(_rndGen, ppDistance);
particle.MoveTo(rndPosition);
primaryParticles.Add(particle);
}
private bool IsRandomPositionValid(
Cluster nextCluster,
List <Cluster> depositedCluster,
Random rndGen,
double distance,
INeighborslist neighborslist)
{
bool found;
// Get a new random position for the COM on the sphere around the deposited cluster
var rndPosition = ParticleFormationUtil.GetRandomPosition(rndGen, distance);
// Move the cluster to that position on the sphere
nextCluster.MoveTo(rndPosition);
// Check if that random position is valid (no overlap, but connection between nextCluster an the deposited cluster)
found = IsClusterPositionValid(nextCluster, neighborslist, depositedCluster);
return(found);
}
