Hi, I was hoping that I can get some clarification about the scaling in QS. I read through Comp. Phys. Comm. 167 (2005) 103. My background is PW methods. There are two ways to obtain the KS ground state in QS: 1. SCF + traditional diagonalization (TD) - The construction of the KS matrix is approximately O(N ln N) < O (N^(1+epsilon)) - TD scales as M^3 N is the number of occupied orbitals ?? M is the number of basis functions Fig. 4 on p. 110 of the article uses N only, instead of M and N. I guess one parameter indicative of system size was used instead of multiple parameters. Also, could someone comment on the memory requirement using SCF + TD. 2. OT - On p. 117, the text states that in the most optimal situation the method scales as M*N^2 and M^2*N in the worst case (non-sparse) scenario. - The memory scales as O(M*N) which I is also similar to a PW method but with a localized basis M is substantiall smaller. I imagine the other terms that contribute to the memory scaling, e.g. potential, charge density, etc. are negligible ?? -- Nichols A. Romero, Ph.D. 1613 Denise Dr. Apt. D Forest Hill, MD 21050 443-567-8328 (C) 410-306-0709 (O)