private double[] calculateSocialVelocity(int particle, double r2) {
		double[] socialVelocity = new double[position[particle].length];
		int nBest = neighbourhood.neighbourhoodBest(particle);
		for(int k = 0; k < socialVelocity.length; k++){
			socialVelocity[k] = socialConstant * r2 * (personalBest[nBest][k] - position[particle][k]);
		}
		return socialVelocity;
	}