[CP2K:4458] neb : question about the number of scf optimizations for each band step for each replica

Andrea Floris an.f... at gmail.com
Mon May 20 11:14:42 UTC 2013

Dear Teo,

I attach the input and output and all relevant files.

My problem is in the BAND* files , whose number is indeed equal to the
number of replica (three in my case).
If you in one of these files (prefix is neba) do

grep -i  'Band  Step  Nr.'  neba-BAND1.out

you have as output something like
 ** Band  Step  Nr. :   13
 ** Band  Step  Nr. :   13
 ** Band  Step  Nr. :   13
 ** Band  Step  Nr. :   13
 ** Band  Step  Nr. :   13
 ** Band  Step  Nr. :   14
 ** Band  Step  Nr. :   14
 ** Band  Step  Nr. :   14

so, e.g. 5 optimizations (but geometrical or purely electronic scf???) in
the band  step 13, and 3 in the band step 14...
That's the point I don't understand...

Moreover, I also do not understand why this is done *also* for the end
points, when you choose to not optimize
the initial and final replica...For example in my case here replica 1 was
fixed.  In fact in the


file, the energy of replica 1 is fixed, i.e. it has always the same energy
through the band optimization steps. But in the file  neba-BAND1.out many
total energies are found...
one for each scf optimization.

Thanks in advance for you answer,


On Mon, May 20, 2013 at 9:54 AM, Teodoro Laino <teodor... at gmail.com>wrote:

> >>
> >> 1. why  more than one scf optimization is performed? (every
> optimization being achieved with ~40 scf steps)
> > it depends on how many processors you are using and how many processors
> per replica you requested. On the top of that, the number of scf
> optimisations depends also on the type of optimiser you are using.
> > Again without an input is almost useless to cover all possible things
> you may see.
> Correction: forget about the parallel setup - you should always have a
> number of BAND* files equal to the number of frames of your NEB.
> So not sure at all what you are seeing… (probably it is only the output of
> the OUTER_SCF cycle)
> In any case, without input..
> >
> >> 2. Are these purely electronic optimizations, or there is a geometrical
> minimization involved?
> > the geometry optimisation steps are not shown in the *BAND* output
> >
> > Regards
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 Dr Andrea Floris
 Research Associate
 King's College London
 Strand, London WC2R 2LS
 United Kingdom
 Phone: +44 (0) 207 848 2064
 Fax    : +44 (0) 207 848 2420
 Location:  Strand Building, 4th floor, Room 4.02
 Emails: andrea... at kcl.ac.uk, an.f... at gmail.com
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