On 1/9/07, Lawrence Lee <lawrence_lee_lee at yahoo.com.hk> wrote: > Dear all, > > Is it really necessary that when using PWSCF to do molecular dynamics, the > following: > > nosym=.true. > > had to be used? If yes, why?
please look at the documentation of the nosym flag! pw.x tries to minimize the number of k-points needed by eliminating symmetry equivalent ones. those can be quite a few, if you have a very symmetric starting structure. as soon as you move atoms, however, those k-points may no longer be equivalent, but the code assumes that the number of k-points does not change during a calculation. similarly point group symmetries are used to speed up the calculation in several places. cheers, axel. > > Lawrence > > _______________________________________ > YM - ???? > ??????????????????????????????????????????? > http://messenger.yahoo.com.hk -- ======================================================================= Axel Kohlmeyer akohlmey at cmm.chem.upenn.edu http://www.cmm.upenn.edu Center for Molecular Modeling -- University of Pennsylvania Department of Chemistry, 231 S.34th Street, Philadelphia, PA 19104-6323 tel: 1-215-898-1582, fax: 1-215-573-6233, office-tel: 1-215-898-5425 ======================================================================= If you make something idiot-proof, the universe creates a better idiot.
