The ABINIT Users Mailing List ( CLOSED )

[Andriy Nevidomskyy <ahn22@phy.cam.ac.uk>]

Dear Developers of ABINIT,

I have the following question to ask. What is the present status of the
parallelization over bands in ABINIT?

       The 'Features' file gives the following info:
"B.1. For ground-state calculations, the code has been parallelized 
on the k-points, on the spins, on the bands,
and on the FFT grid and plane wave coefficients."
 From what is written above one would assume that parallelizations of all
kinds should work equally well (with MPI).
            However:
 I was running the parallel version of ABINIT_3.4.3 on IBM-SP3 machine,
but whatever I tried, the band parallelization wouldn't work. 
For example, in the case of 1 k-point
all the load is carried by only ONE processor, while the others are idle!

I used the following parameters in the input file, as documented in
the list of input variables:
   wfoptalg 1     # blocked CG algorithm minimization 
   nbdblock 8     # here, say, 8 - number of available processors
I played around with different values of <nbdblock>, being integer
divisors
of the total number of processors, but it had no effect on the run. 
In fact, the sequential version of ABINIT did better job in all cases! 

Am I missing something essential, which is why the parallel version
doesn't work, or is there any other reason for this?
I would be very grateful for your help.

Yours Sincerely,
Andriy Nevidomskyy

P.S> The parallelization over k-points seems to be working fine. 
Unfortunately only when nkpt=integer*number_of_processors.


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|                        Mr Andriy Nevidomskyy                     |     
|                                                                  |
|     TCM Group, Cavendish Laboratory, University of Cambridge     |   
|          Madingley Road, Cambridge CB3 0HE United Kingdom        |
| Tel:+44-1223-337433,Fax:+44-1223-337356, E-mail: ahn22@cam.ac.uk |
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