/// <summary>
/// Update the velocity of a particle
/// </summary>
/// <param name="particleIndex">index of the particle in the swarm</param>
/// <param name="particlePosition">the particle current position vector</param>
protected void UpdateVelocity(int particleIndex, double[] particlePosition)
{
int i = particleIndex;
double[] vtmp = new double[particlePosition.Length];
// Standard PSO formula
// inertia weight
m_va.Mul(m_velocities[i], m_inertiaWeight);
// cognitive term
m_va.Copy(vtmp, m_bestVectors[i]);
m_va.Sub(vtmp, particlePosition);
m_va.MulRand(vtmp, m_c1);
m_va.Add(m_velocities[i], vtmp);
// social term
if (i != m_bestVectorIndex)
{
m_va.Copy(vtmp, m_pseudoAsynchronousUpdate ? m_bestVectors[m_bestVectorIndex] : m_bestVector);
m_va.Sub(vtmp, particlePosition);
m_va.MulRand(vtmp, m_c2);
m_va.Add(m_velocities[i], vtmp);
}
}
/**
* Update the velocity of a particle
*
* @param particleIndex index of the particle in the swarm
*/
protected void UpdateVelocity(int particleIndex)
{
double[] particlePosition = _particles[particleIndex].LongTermMemory;
double[] vtmp = new double[particlePosition.Length];
// Standard PSO formula
// inertia weight
VectorAlgebra.Mul(_velocities[particleIndex], inertiaWeight);
// cognitive term
VectorAlgebra.Copy(vtmp, _bestVectors[particleIndex]);
VectorAlgebra.Sub(vtmp, particlePosition);
VectorAlgebra.MulRand(_rnd, vtmp, this.c1);
VectorAlgebra.Add(_velocities[particleIndex], vtmp);
// social term
if (particleIndex != _bestVectorIndex)
{
VectorAlgebra.Copy(vtmp, _bestVector);
VectorAlgebra.Sub(vtmp, particlePosition);
VectorAlgebra.MulRand(_rnd, vtmp, c2);
VectorAlgebra.Add(_velocities[particleIndex], vtmp);
}
}