[Pw_forum] Error ortho went bananas

[dkartik]

Many many thanks to Giuseppe Mattioli and Ari P Seitsonen, it worked.
one more thing i am unable to register for svn version of QE, is there
any other way. 

Thanks 

Kartikeya Dixit 

Ph.D scholar 

IIT Kanpur, India 

Message: 6
Date: Sat, 17 Jun 2017 21:00:21 +0200 (CEST)
From: Ari P Seitsonen <Ari.P.Seitsonen at iki.fi>
Subject: Re: [Pw_forum] Error ortho went bananas
To: PWSCF Forum <pw_forum at pwscf.org>
Message-ID: <alpine.DEB.2.20.1706172051020.17409 at kubo.chimie.ens.fr>
Content-Type: text/plain; charset="iso-8859-1"

Adding to Giovanni's response,

   If this is the same GTH/HTH pseudo potential that we used recently
(I-Chun Lin et alia x2) to simulate liquid water, we found that at least
120 Ry was required for reasonable converergence (NVT; NPT would have
required much more). 80-90 Ry is more or less sufficient for a
Troullier-Martins-type pseudo potential. Oh, and PBE requires somewhat
less than BLYP, that we used actually.

     Greetings from Paris 6e,

        apsi

-=*=-=*=-=*=-=*=-=*=-=*=-=*=-=*=-=*=-=*=-=*=-=*=-=*=-=*=-=*=-=*=-=*=-=*=-=*=-
   Ari Paavo Seitsonen / Ari.P.Seitsonen at iki.fi /
http://www.iki.fi/~apsi/ [1]
     Ecole Normale Sup?rieure (ENS), D?partement de Chimie, Paris
     Mobile (F) : +33 789 37 24 25    (CH) : +41 79 71 90 935

On Fri, 16 Jun 2017, Giuseppe Mattioli wrote:

>
> ?
>
> Dear Kartikeya Dixit
>
> ?
>
> > ecutwfc=20.0
>
> > O 16.00 O.pbe-hgh.UPF
>
> ?
>
> 20.0 Ry seems to be a poorly unconverged value for this hard Hartwigsen-Goedecker-Hutter O.pbe-hgh.UPF
> norm conserving pseudopotential. I would rather expect a converged value of 80.0 Ry.
>
> *N.B.*: If you do not understand this comment you should start from tutorials before performing actual
> simulations.
>
> ?
>
> Moreover
>
> ?
>
> Variables: nr1b, nr2b, nr3b
>
> ?
>
> Type: INTEGER
>
> Description: dimensions of the "box" grid for Ultrasoft pseudopotentials
>
> must be specified if Ultrasoft PP are present
>
> ?
>
> There are no ultrasoft PP in your calculation
>
> ?
>
> Variable: q2sigma
>
> ?
>
> Type: REAL
>
> Default: 0.1
>
> Description: ecfixed, qcutz, q2sigma: parameters for modified functional to be
>
> used in variable-cell molecular dynamics (or in stress calculation).
>
> "ecfixed" is the value (in Rydberg) of the constant-cutoff;
>
> "qcutz" and "q2sigma" are the height and the width (in Rydberg)
>
> of the energy step for reciprocal vectors whose square modulus
>
> is greater than "ecfixed". In the kinetic energy, G^2 is
>
> replaced by G^2 + qcutz * (1 + erf ( (G^2 - ecfixed)/q2sigma) )
>
> See: M. Bernasconi et al, J. Phys. Chem. Solids 56, 501 (1995)
>
> ?
>
> You are not performing a variable-cell molecular dynamics simulation.
>
> ?
>
> HTH
>
> Giuseppe
>
> ?
>
> On Thursday, June 15, 2017 05:21:52 PM dkartik wrote:
>
> > Hello everyone
>
> >
>
> > I am getting an error ortho went bananas while running the following
>
> > code. As it was discussed in various pw forums we can get rid of this
>
> > problem by reducing dt or increasing ortho_max. But none of them helped.
>
> > Any small hint or help is welcomed.
>
> >
>
> > Thanks
>
> > Kartikeya Dixit
>
> > Ph.D Scholar
>
> > IIT Kanpur, India
> 

Links:
------
[1] http://www.iki.fi/%7Eapsi/
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