[Pw_forum] Error in routine bfgs (1): dE0s is positive which should never happen

[Paolo Giannozzi]

Please send me an output showing the problem you mention. Paolo

On Fri, Sep 23, 2016 at 11:31 AM, Alaska Subedi <asubedi at gmail.com> wrote:

> On Thu, Sep 22, 2016 at 6:03 PM, Paolo Giannozzi <p.giannozzi at gmail.com>
> wrote:
> > Once the error is detected, the code stops immediately and prints nothing
> > useful. Where do you see that there are no cell parameters? And when:
> during
> > a variable-cell calculation, or also (or only) in a fixed-cell one? If I
> > remember correctly, cell parameters are reprinted on putput at each step
> in
> > the former case, never in the latter.
>
> In a vc-relax calculation, the code prints atomic_positions but not
> cell_parameters after this error. Generally, vc-relax prints both
> cell_parameters and atomic_positions. But this does not happen when
> the code stops with this error. It would be nice if it also printed
> cell_parameters before exiting.
>
> Thanks,
> Alaska
>
>
> >
> > Unfortunately the code performing the various MD and structural
> > optimizations is rather obscure and it is not straightforward to figure
> out
> > how to modify it.
> >
> > Paolo
> >
> > On Thu, Sep 22, 2016 at 2:56 PM, Alaska Subedi <asubedi at gmail.com>
> wrote:
> >>
> >> Dear Paolo,
> >>
> >> Sorry to resurrect this after a long time.
> >>
> >> This problem is innocuous but annoying nonetheless. I am using QE to
> >> relax structures generated by USPEX. For around five percent of the
> >> structures, I get this error. When this error happens, pw.x exits by
> >> only printing atomic positions but not the cell parameters. This gives
> >> problems to USPEX.
> >>
> >> I tried to find which call to output_tau is responsible for this, to
> >> no avail. I'd greatly appreciate if someone can point me to a
> >> modification that will make the code output both the cell_parameters
> >> and atomic_positions during exit after this error.
> >>
> >> Thanks,
> >> Alaska
> >>
> >>
> >>
> >> On Mon, Sep 22, 2014 at 9:52 PM, Paolo Giannozzi
> >> <paolo.giannozzi at uniud.it> wrote:
> >> > This kind of errors invariably happens when you are very close
> >> > to the minimum and you have some numerical noise on forces. It
> >> > is useless in my opinion to insist: your system is sufficiently
> >> > relaxed
> >> >
> >> > Paolo
> >> >
> >> > On Mon, 2014-09-22 at 13:29 +0530, amitharani wrote:
> >> >> Hi
> >> >> I am getting an error { Error in routine bfgs (1): dE0s is positive
> >> >> which should never happen }. The output file is attached for your
> kind
> >> >> perusal.This is the 2nd time I am getting the same error
> consecutively.
> >> >> I followed what Nick had suggested on the pwforum to take the relaxed
> >> >> co-ordinates, make a new input file and resubmit, but it didn't
> >> >> work.Thanks.
> >> >>
> >> >>
> >> >> _______________________________________________
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> >> >> http://pwscf.org/mailman/listinfo/pw_forum
> >> >
> >> > --
> >> > 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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> >> > Pw_forum at pwscf.org
> >> > http://pwscf.org/mailman/listinfo/pw_forum
> >> _______________________________________________
> >> Pw_forum mailing list
> >> Pw_forum at pwscf.org
> >> http://pwscf.org/mailman/listinfo/pw_forum
> >
> >
> >
> >
> > --
> > Paolo Giannozzi, Dip. Scienze Matematiche Informatiche e Fisiche,
> > Univ. Udine, via delle Scienze 208, 33100 Udine, Italy
> > Phone +39-0432-558216, fax +39-0432-558222
> >
> >
> > _______________________________________________
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> > Pw_forum at pwscf.org
> > http://pwscf.org/mailman/listinfo/pw_forum
> _______________________________________________
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>



-- 
Paolo Giannozzi, Dip. Scienze Matematiche Informatiche e Fisiche,
Univ. Udine, via delle Scienze 208, 33100 Udine, Italy
Phone +39-0432-558216, fax +39-0432-558222
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