code: public static double rmsd(Atom[] x, Atom[] y) {
  		return CalcPoint.rmsd(atomsToPoints(x), atomsToPoints(y));
  	}
docs: Calculate the RMSD of two Atom arrays, already superposed.
  
  @param x
  array of Atoms superposed to y
  @param y
  array of Atoms superposed to x
  @return RMSD