[Pw_forum] supercell contraction and cell_factor parameter

[Paolo Giannozzi]

On Thu, 2012-07-12 at 15:54 +0000, Zhihui Zhu wrote:

> Can anyone please explain what the cell-factor variable represent?

it represent a not-so-smart solution to a purely technical problem.
the code computes interpolation tables in reciprocal space at the
beginning of the calculation. During a variable-cell optimization,
if the cell contracts in real space, it expands in reciprocal space.
Interpolation tables extend up to cell_factor*q_max, where q_max
is what is needed at the beginning of the calculation. It does not
affect in any way the results.

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