The ABINIT Users Mailing List ( CLOSED )

[Xavier Gonze <gonze@pcpm.ucl.ac.be>]

Dear MT Storr,

As Michel and Jean-Francois mentioned, mkmem should be the
ratio between the number of k points and the number of processor.
So, I do not understand why mkmem is equal to 432 (the number
of k points) on your 8 proc Linux cluster !
There seems to be a problem on that config.
If you want to investigate this further, mkmem is determined
in the routine invars1.f .
In particular, see lines 702-705 (version 4.0.4)

   if(nkpt_me<mkmem .and. nkpt_me/=0)then
    write(message, '(a,a,a)' ) &
&    ' Resetting ',nm_mkmem(ii),' to nkpt_me to save memory space.'
    mkmem=nkpt_me

will use the number of processor for that particular processor,
nkpt_me in place of the default value of mkmem. It is very
likely that, in your case, nkpt_me is determined in lines 592-593 of that
routine. Also, check at line 557 whether the
number of processor seen by ABINIT (mpi_enreg%nproc)
is correctly 8, or only 1 (in which case, you are running
in sequential !). Is your CPP (C-preprocessor) running
correctly on your Linux cluster ? You might preprocess
manually the invars1.f file, with the options that you set in the
makefile_macros, to see whether the file has been correctly
treated.

Additional information : if there is a problem of memory,
set mkmem=0 in the input fuile. You will be using files
to store the wavefunctions.

Good continuation,
Xavier

As Michel mentioned,
M.T.Storr wrote:
> HI,
>
> I have a quick question concerning Abinit memory requirements. I have 
> tried running an identical calculation on two different machines as 
> outlined below, however upon running the calculations the calculated 
> memory requirements are totally different. As can be seen the echoed 
> parameters are identical in both cases except for the mkmem variable yet 
> on one system the required memory is said to be 374 Mb, while on the other it 
> is said to be 4244 Mb. My question is therefore where does the mkmem 
> variable come from and why is there such a vast difference in the required 
> memory for the same calculation.
>
> On an IBM SP3 machine with running on 28 processors -
>
>  DATASET    1 : space group P-1 (#  2); Bravais aP (primitive triclinic)
> ============================================================================
>  Values of the parameters that define the memory need for DATASET  1.
>    intxc =         0  ionmov =         3    iscf =         5     ixc =
> 1
>   lmnmax =         3   lnmax =         3   mband =        34  mffmem =
> 1
>    mgfft =        60   mkmem =        31 mpssoang=         4     mpw =
> 9200
>   mqgrid =      1201   natom =         3    nfft =    216000    nkpt =
> 432
>   nloalg =         4  nspden =         2 nspinor =         1  nsppol =
> 2
>     nsym =         2  n1xccc =      2501   ntype =         2  occopt =
> 1
> ============================================================================
>  This job should need less than                     374.572 Mbytes of
> memory.
>  Rough estimation (10% accuracy) of disk space for files :
>  WF disk file :     27.830 Mbytes ; DEN or POT disk file :      3.298
> Mbytes.
> ============================================================================
>
> While on a Linux cluster with 8 processors-
>
>  DATASET    1 : space group P-1 (#  2); Bravais aP (primitive triclinic)
> ============================================================================
>  Values of the parameters that define the memory need for DATASET  1.
>    intxc =         0  ionmov =         3    iscf =         5     ixc =
> 1
>   lmnmax =         3   lnmax =         3   mband =        34  mffmem =
> 1
>    mgfft =        60   mkmem =       432 mpssoang=         4     mpw =
> 9200
>   mqgrid =      1201   natom =         3    nfft =    216000    nkpt =
> 432
>   nloalg =         4  nspden =         2 nspinor =         1  nsppol =
> 2
>     nsym =         2  n1xccc =      2501   ntype =         2  occopt =
> 1
> ============================================================================
>  This job should need less than                    4244.696 Mbytes of 
> memory.
>  Rough estimation (10% accuracy) of disk space for files :
>  WF disk file :     27.830 Mbytes ; DEN or POT disk file :      3.298
> Mbytes.
> ============================================================================