code: public Matrix4d superposeAfterRmsd() {
  
  		if (!rmsdCalculated) {
  			throw new IllegalStateException("The RMSD was not yet calculated. Use the superpose() method instead.");
  		}
  
  		getRotationMatrix();
  		if (!centered) {
  			calcTransformation();
  		} else {
  			transformation.set(rotmat);
  		}
  		return transformation;
  	}
docs: The QCP method can be used as a two-step calculation: first compute the
  RMSD (fast) and then compute the superposition.
  
  This method assumes that the RMSD of two arrays of points has been
  already calculated using {@link #getRmsd(Point3d[], Point3d[])} method
  and calculates the transformation of the same two point arrays.
  
  @param fixed
  @param moved
  @return transformation matrix as a Matrix4d to superpose moved onto fixed
  point arrays