[Pw_forum] parallelization

[Paolo Giannozzi]

On Thu, 2013-05-23 at 21:47 +0000, vijaya subramanian wrote:

> I would like to know what the parallelization info given in the
> pwscf output file means.  

"sticks" = columns of G-vectors along crystal axis 3 (usually z)

 "dense" = G-vectors in the  "dense" grid, such that G^2 < ecutrho
"smooth" = G-vectors in the "smooth" grid, such that G^2 < 4*ecut
    "PW" = G-vectors in the plane-wave basis set, such that (k+G)^2<ecut

First 3 columns: number of sticks, last 3 columns: number of G-vectors

For a good parallelization, Min and Max are very similar and equal
to Sum (last row) divided by the number of processors (Npw) used in
plane-wave parallelization. Also, the third FFT dimension (nr3s smooth
grid, nr3 dense grid) should be a multiple of Npw.

> sticks:   dense  smooth     PW     G-vecs:    dense   smooth      PW
> Min         261      34      9                80945     3842     535
> Max         262      35     10                80960     3903     550
> Sum       65895    8697   2339             20399419   976925  136381

> Are both Plane Wave and k-point parallelization  set by -npool?

they are set by npool and by the totalnumber of precessor Nproc:
Npw=Nproc/npool

> What were the values of npool used in the "scalability for medium
> sized systems" section? 

1 for Gamma-point calculations, 4 for PSIWAT

> where can I find Nw and Ng in the output file

see above

> and how is the number of Kohn Sham states to be calculated determined
> for an scf calc?

for an insulator, as the number of valence bands; for a metal, 20% more

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