/// <summary>
/// Construct PSO trainer.
/// </summary>
/// <param name="theParticles">The particles to use.</param>
/// <param name="theCalculateScore">The score object.</param>
public TrainPSO(IMLMethod[] theParticles,
IScoreFunction theCalculateScore)
{
_particles = theParticles;
_score = theCalculateScore;
int vectorSize = theParticles[0].LongTermMemory.Length;
int particleCount = theParticles.Length;
_bestVectors = new double[particleCount][];
_velocities = new double[particleCount][];
_bestScores = new double[particleCount];
for (int i = 0; i < particleCount; i++)
{
_bestVectors[i] = new double[vectorSize];
_velocities[i] = new double[vectorSize];
}
_bestVectorIndex = -1;
_bestVector = new double[vectorSize];
foreach (double[] velocity in _velocities)
{
VectorAlgebra.Randomise(_rnd, velocity, this.maxVelocity);
}
}
/// <summary>
/// Update the velocity, position and personal
/// best position of a particle.
/// </summary>
/// <param name="particleIndex">index of the particle in the swarm</param>
/// <param name="init">if true, the position and velocity
/// will be initialised. </param>
public void UpdateParticle(int particleIndex, bool init)
{
int i = particleIndex;
double[] particlePosition = null;
if (init)
{
// Create a new particle with random values.
// Except the first particle which has the same values
// as the network passed to the algorithm.
if (m_networks[i] == null)
{
m_networks[i] = (BasicNetwork)m_bestNetwork.Clone();
if (i > 0)
{
m_randomizer.Randomize(m_networks[i]);
}
}
particlePosition = GetNetworkState(i);
m_bestVectors[i] = particlePosition;
// randomise the velocity
m_va.Randomise(m_velocities[i], m_maxVelocity);
}
else
{
particlePosition = GetNetworkState(i);
UpdateVelocity(i, particlePosition);
// velocity clamping
m_va.ClampComponents(m_velocities[i], m_maxVelocity);
// new position (Xt = Xt-1 + Vt)
m_va.Add(particlePosition, m_velocities[i]);
// pin the particle against the boundary of the search space.
// (only for the components exceeding maxPosition)
m_va.ClampComponents(particlePosition, m_maxPosition);
SetNetworkState(i, particlePosition);
}
UpdatePersonalBestPosition(i, particlePosition);
}
