[Wien] Parallelization on one computer with 8 cpus

[Peter Blaha]

Please read the UG more carefully.
I think parallelization is explained pretty well.
In particular you have to understand the difference between k-parallel 
and fine-grane mpi-parallel mode.

The syntax for lapw1/2 parallelization is:

speed:hostname[:cores for mpi] [other_hostnames_for_mpi]

So the first number is a relative speed number. Useful if you want to 
combine a fast and a slow computer in k-parallel mode. For you: always 1

second ist hostname, in your case it can be "localhost"

:8  would mean 8 fold mpi-parallel. It requires that you have installed 
properly the mpi-version (this is a bit more difficult) AND that you 
have a bigger case which runs reasonable in mpi-mode. If you need 74 
k-points, most likely this is NOT the case.

I'd set OMP_NUM_THREAD=2 and then use:

granularity:1
1:localhost
1:localhost
1:localhost
1:localhost
residue: localhost
#  only if you have mpi installed !!
lapw0: localhost:8
dstart: localhost:8

This will start 4 jobs with 18k and a residue job with 2 k.
Each will use 2 cores because of OMP_NUM_THREADS when wien2k is 
installed properly.

On 03/16/2014 03:12 PM, Juliet parker wrote:
> *Hi dear WIEN2k users*
> I want to run wien2k in the parallel mode (i.e. run_lapw -p -cc 0.0001)
> on only one computer which has 8 CPUs, /i.e./ all 8 CPUsbe used.
> I have read user-guide (section 5.5.3), but it was not explained
> “Parallelization” on only one computer.
> The default setting of “.machines” file for my system is as follows:
> 1:localhost
> 1:localhost
> granularity:1
> extrafine:1
> As I have understood from user-guide, I should edit this file as follows
> (I have 74 k-points):
> -------------------------------------------------------------------------------------
> granularity:1
> 9:localhost
> 9:localhost
> 9:localhost
> 9:localhost
> 9:localhost
> 9:localhost
> 9:localhost
> 9:localhost
> residue: localhost:2
> lapw0: localhost:8
> dstart: localhost:8
> # 9kpoints * 8cups =72 kpoints from 74 kpoints, so 2 additional k-points
> were assigned to “residue:localhost:2”
> OR as:
> granularity:1
> 74:localhost:8
> lapw0: localhost:8
> dstart: localhost:8
> Are such “.machine” files true?
> Could you please help me with this problem?
> Thank you
> J.Parker
>
>
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-- 

                                       P.Blaha
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Peter BLAHA, Inst.f. Materials Chemistry, TU Vienna, A-1060 Vienna
Phone: +43-1-58801-165300             FAX: +43-1-58801-165982
Email: blaha at theochem.tuwien.ac.at    WWW: 
http://info.tuwien.ac.at/theochem/
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