On Tue, 13 Nov 2007, alan chen wrote: AC> Dear PWSCF users,
dear hanghui, AC> I am now trying to impose some constraints in the ionic dynamics. AC> However, after I checked the code I found that if I use 'bfgs' algorithm for AC> 'relax' calculation, the constraints are not implemented in the code. It implementing constraints in a geometry optimization (unlike in an MD) is a non-trivial task. many codes i know "fake" them by using a very, very stiff force constant. using damped dynamics is a reasonable alternative to BFGS and will allow constraints. ceers, axel. AC> seems that contraints can only be imposed in the molecule dynamics using AC> Verlet algorithm. Is that true? Any one can share his or her experience in AC> imposing contraints in the ionic dynamics? AC> Thank you very much. AC> AC> Hanghui AC> Department of Physics AC> Yale University AC> -- ======================================================================= 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.
