[Pw_forum] the smooth step function vc-relax

[Paolo Giannozzi]

On Thu, 2012-11-01 at 13:05 -0700, Yongsheng Zhang wrote:

> 
> There is a simply question about the smooth step function  [G^2 + qcutz * (1 + erf ( (G^2 - ecfixed)/q2sigma) )]. This function is recommended in the MD simulations, like vc-md and vc-cp. But why not in the vc-relax?

you can do that as well. Not sure you will gain much, though.
I htink that the smooth step function is more useful in MD
calculations where it prevents unphysical "jumps" during
the run

P.
-- 
Paolo Giannozzi, IOM-Democritos and University of Udine, Italy