On Mon, 2013-10-07 at 09:48 +0300, Uri Argaman wrote: > It's worth to set nimage equal to the number of q-points > in the phonon calculation?
not necessarily so. Different wave-vectors may have different workloads: not by order of magnitudes, but a low-symmetry wave-vector may easily take 5 times more CPU than a high-symmetry one. > In addition I want to ask how the complexity of the phonon calculation > depends on the number of the k-points (in the PW calculation) roughly linearly, but the number of actual k-points in phonon calculations depends upon the symmetry and the wave-vector > and how the number of k-points affects the accuracy of the phonon > calculation. more or less (more rather than less) in the same way as it affects the calculation of other structural properties; quantities related to the electric field (effective charges and dielectric tensors) tend to converge more slowly with the number of k-points P. -- Paolo Giannozzi, Dept. Chemistry&Physics&Environment, Univ. Udine, via delle Scienze 208, 33100 Udine, Italy Phone +39-0432-558216, fax +39-0432-558222