Comment on “Fast determination of the optimal rotational matrix for macromolecular superpositions” [J. Comp. Chem. 31, 1561 (2010)]

Recently Liu et al. published a fast algorithm to solve the eigenvector problem arising in the quaternion‐based method for the rotational superposition of molecular structures (J Comput Chem 2010, 31, 1561.). In this Comment, it is shown that the construction of the 4 × 4 matrix to be diagonalized—and not the diagonalization itself—represents the dominating part of the computational effort for the quaternion‐based solution of the rotational superposition problem if molecules with more than about 100 atoms are considered. © 2010 Wiley Periodicals, Inc. J Comput Chem, 2010