[QE-developers] Standard plane-wave parallelization

[Thomas Brumme]

Dear all,

I understand that the standard parallelization in QE is done via the FFTs
which also results in a quite good speed up AND memory reduction.
Of course, the communication between CPUs needs to be fast.

Yet, why is the most important number here the 3rd dimension? Is it
difficult to implement that the most important dimension is actually the
largest one? Or would it be "easier" to (internally) rotate the system such
that the 3rd dimension is the largest and then do the computations and
rotate back?

I'm asking since I have a large slab system in which z ist not the largest
dimension and thus I get memory problems on the cluster. Rotating
the system such that the slab is not in xy but in yz I can reduce the
memory needed per task... So, I can do this manually but it would be
easier if this is automatically taken care of ;)

Kind regards

Thomas

-- 
Dr. rer. nat. Thomas Brumme
Wilhelm-Ostwald-Institute for Physical and Theoretical Chemistry
Leipzig University
Phillipp-Rosenthal-Strasse 31
04103 Leipzig

Tel:  +49 (0)341 97 36456

email: thomas.brumme at uni-leipzig.de