code: public int[] getTopoEquivClassbyHuXu(IAtomContainer atomContainer) throws NoSuchAtomException {
          double nodeSequence[] = prepareNode(atomContainer);
          nodeMatrix = buildNodeMatrix(nodeSequence);
          bondMatrix = buildBondMatrix();
          weight = buildWeightMatrix(nodeMatrix, bondMatrix);
          return findTopoEquivClass(weight);
      }
docs: Get the topological equivalent class of the molecule.
  
  @param atomContainer
  atoms and bonds of the molecule
  @return an array contains the automorphism partition of the molecule