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[BOTTIN Francois <francois.bottin@cea.fr>]

Hi Mohua,

I don't understand your problem:
You don't obtain a calculation 8 times faster than in sequential?
You expected to 8 times less bands per processor?

It's seems that your parallel input variables are well echoed by the 
code (in the log): npfft=npkpt=1 and npband=8.
So your calculation seems to be performed in paralell.

Note that the band-fft parallelization is also a PW parallelization (it 
depends on the part of the code you are interested in).
So, the only way to convince yourself that you perform (or not) 
calculations in parallel is to execute the same
job in sequential and see if mpw is 8 times larger.

Regards,
Francois

Mohua Bhattacharya a écrit :
> Hello,
>
> I am trying to test band fft parallelization for a Au system with 648 
> bands and 8 processors. I am using v 6.0.1.
> Here are snippets of the input file , log file and the output file. It 
> looks like it is not doing parallelization over bands. Any input is 
> hugely appreciated.
> Thanks for your time,
> Regards
> Mohua
>
>
> Input:
>
> paral_kgb 1
> npband 8 #27
> npfft 1 #4
> timopt -1
> fftalg 401 wfoptalg 4 fft_opt_lob 2
> iprcch 0 intxc 0
>
>
>
>
>
>
> Output:
>
> Symmetries : space group Pm -3 m (#221); Bravais cP (primitive cubic)
> ================================================================================
> Values of the parameters that define the memory need of the present run
> intxc = 0 ionmov = 0 iscf = 7 xclevel = 1
> lmnmax = 2 lnmax = 2 mband = 648 mffmem = 1
> P mgfft = 36 mkmem = 1 mpssoang= 3 mpw = 286
> mqgrid = 3001 natom = 107 nfft = 46656 nkpt = 1
> nloalg = 4 nspden = 1 nspinor = 1 nsppol = 1
> nsym = 48 n1xccc = 2501 ntypat = 1 occopt = 3
> ================================================================================
> P This job should need less than 32.684 Mbytes of memory.
> Rough estimation (10% accuracy) of disk space for files :
> WF disk file : 2.830 Mbytes ; DEN or POT disk file : 0.358 Mbytes.
> ================================================================================
>
> -outvars: echo values of preprocessed input variables --------
> acell 2.3010000000E+01 2.3010000000E+01 2.3010000000E+01 Bohr
> amu 1.96966540E+02
> ecut 2.50000000E+00 Hartree
> enunit 2
> fftalg 401
> fft_opt_lob 2
> iprcch 0
> kpt 2.50000000E-01 2.50000000E-01 2.50000000E-01
> kptrlen 4.60200000E+01
> kptrlatt 2 0 0 0 2 0 0 0 2
> P mkmem 1
> natom 107
> nband 648
> ngfft 36 36 36
> nkpt 1
> nline 1
> npband 8
> npulayit 10
> nstep 1
> nsym 48
> ntypat 1
>
>
> P newkpt: treating 648 bands with npw= 286 for ikpt= 1 by node 0
>
>
> Log:
>
> npfft, npband and npkpt 1 8 1
> mpi_enreg%sizecart(1),np_fft 1 1
> mpi_enreg%sizecart(2),np_band 8 8
> mpi_enreg%sizecart(3),np_kpt 1 1
>
>
>
> For dataset= 1 a possible choice for less than 0 processors is:
> nproc npkpt npband npfft bandpp
>
> chkinp: WARNING -
> When k-points/bands/FFT parallelism is activated
> (paral_kgb=1), only MPI-IO input/output is allowed !
> accesswff/=1 in your input file
> You will not be able to perform input/output !
>
>
> kpgio: loop on k-points done in parallel 


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Francois Bottin                    tel: 01 69 26 41 73
CEA/DIF                            fax: 01 69 26 70 77
BP 12 Bruyeres-le-Chatel         email: Francois.Bottin@cea.fr
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