[Pw_forum] pw.x memory usage

[Paolo Giannozzi]

On Mon, 2014-07-07 at 15:27 +0100, Pierre-André Cazade wrote:

> This requires 97GB of RAM [...] it is normal that QE requires
> such a vast amount of memory

a 268-atom cell with some empty layers is not small. Consider that
the latest QE version stores by default all wavefunctions in memory,
since I/O is usually a more serious bottleneck than RAM. If you start
the code with "K_POINTS gamma", it should at least start and print out 
some info on largest arrays. A few memory-saving tips are in the
user guide, item 5.0.0.10

P.
-- 
 Paolo Giannozzi, Dept. Chemistry&Physics&Environment, 
 Univ. Udine, via delle Scienze 208, 33100 Udine, Italy
 Phone +39-0432-558216, fax +39-0432-558222