[Pw_forum] Error in routine sym_rho_init_shell "lone vector" with fixed FFT dimension
Paolo Giannozzi
paolo.giannozzi at uniud.it
Fri Feb 7 16:25:14 CET 2014
On Thu, 2014-02-06 at 12:58 +0100, Thomas Gruber wrote:
> I attached 2 inputs files. One with smaller volume works and one with
> greater volume with the corresponding *.out file, which works not. Since
> I have already done phonon calculations for 5 different volumes, I don't
> want to change the FFT dimension. I fixed it to 48 48 200 and the not
> fixed FFT dimension would be 50 50 200.
> Any suggestions?
it works if you reduce by a little bit "ecutrho" from its default value
4*ecutwfc. The problem is that if you keep the FFT grid fixed, you may
"miss" a few G-vectors. The algorithm that divides G-vectors into shells
of vectors transforming into each other cannot work if a shell is
incomplete. Alternatively: remove symmetry, since such algorithm is
used only for symmetrization of the charge density. I have no better
ideas right now: finding an algorithm that is guaranteed to work if
the FFT grid is not sufficient to accommodate the G-vector sphere
up to G^2< ecutrho may require a serious effort
Paolo
> Regards,
>
> Thomas Gruber
>
> On 02/06/2014 12:00 PM, pw_forum-request at pwscf.org wrote:
> > Message: 11
> > Date: Wed, 05 Feb 2014 19:45:00 +0100
> > From: Paolo Giannozzi<paolo.giannozzi at uniud.it>
> > Subject: Re: [Pw_forum] Error in routine sym_rho_init_shell "lone
> > vector" with fixed FFT dimension
> > To: PWSCF Forum<pw_forum at pwscf.org>
> > Message-ID:<1391625900.28572.9.camel at pania.fastwebnet.it>
> > Content-Type: text/plain; charset="UTF-8"
> >
> > Very strange. The error signals a failure in the algorithm
> > that finds shells of G-vectors that transform into each other
> > under symmetry operations. It might however be due to too small
> > FFT dimensions, maybe. It is hard to figure out what happens
> > without an input file.
> >
> > P.
> >
> > On Wed, 2014-02-05 at 15:49 +0100, Thomas Gruber wrote:
> >> > Dear all,
> >> >
> >> > I try to determine the heat capacity at constant pressure and calculate
> >> > the phonon DOS at different volumes. Since I get jumps in free energy
> >> > when the FFT dimension change, I fix it to the one from the starting
> >> > volume. But for on of my systems everything works fine up to 4%
> >> > isotropic increase of the cell axis and at 5% I get the following error
> >> > in the starting scf calculation:
> >> > %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
> >> > Error in routine sym_rho_init_shell (2):
> >> > lone vector
> >> > %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
> >> > This error does not show up, when I do not fix the FFT dimension.
> >> > Without fixing the FFT dimension the FFT dimension is different to the
> >> > one I choose.
> >> > Is there a way to keep my fixed FFT dimension and get rid of this error?
> >> >
> >> > Thanks in advise.
> >> >
> > -- Paolo Giannozzi, Dept. Chemistry&Physics&Environment, Univ. Udine,
> > via delle Scienze 208, 33100 Udine, Italy Phone +39-0432-558216, fax
> > +39-0432-558222
>
>
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--
Paolo Giannozzi, Dept. Chemistry&Physics&Environment,
Univ. Udine, via delle Scienze 208, 33100 Udine, Italy
Phone +39-0432-558216, fax +39-0432-558222
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