code: private double[] computeResidualVector(double[] vector, int centroidIndex) {
  		double[] residualVector = new double[vectorLength];
  		for (int i = 0; i < vectorLength; i++) {
  			residualVector[i] = coarseQuantizer[centroidIndex][i] - vector[i];
  		}
  		return residualVector;
  	}
docs: Computes the residual vector.
  
  @param vector
  The original vector
  @param centroidIndex
  The centroid of the coarse quantizer from which the original vector is subtracted
  @return The residual vector