[QE-users] NON CONVERGENCE OF PHONON CALCULATION DUE TO LIMITED NUMBER OF ITERATIONSR

[Duc-Long Nguyen]

Dear Shuham,

After modifying maxter from 100 to 300, you should recompile ph.x (type 
make in folder PHonon/PH) as I can see the loop stopped after 100 
iterations. Adding to those comments from Dr. Mattioli and Dr. Wolf, you 
may want to reduce 'alpha_mix' to get better convergence.

H.T.H

Duc-Long Nguyen
Graduate student,
TIGP, Academia Sinica, Taiwan

On 10/04/2018 11:42 PM, Shubham Tyagi wrote:
> Respected Sir/Ma'am
> I  am Shubham Tyagi. I m currently pursuing masters in 
> science(Physics) from IIT Jodhpur, India.
> I have taken DFT as my topic for my second-year project. Now I am 
> facing some difficulties regarding that. The difficulty is summed as:
> I was doing phonon calculation for a supercell and I encountered with 
> a problem that the calculations did not converge as the maximum 
> iteration was till 100 only.
> I tried changing the maxter from 100 to 300 but all in vain. This all 
> was for phonon calculation. So can you provide me with some way to 
> increase the number of iterations for phonon calculation?
> The required files are attached
>
>
>
> On Thu, Oct 4, 2018 at 1:57 PM Giuseppe Mattioli 
> <giuseppe.mattioli at ism.cnr.it <mailto:giuseppe.mattioli at ism.cnr.it>> 
> wrote:
>
>
>     Dear Colleague
>
>     First of all please sign your posts to this forum with name and
>     scientific affiliation.
>
>     It's impossible to help you if you do not provide any detail of your
>     calculation. pw.x and ph.x input files are necessary to check if one
>     (among many) critical parameter is likely responsible for your
>     convergence difficulties. This does not imply, of course, that ALL
>     convergence difficulties can be overcome...
>     HTH
>     Giuseppe
>
>     Shubham Tyagi <shubhamtyagi145 at gmail.com
>     <mailto:shubhamtyagi145 at gmail.com>> ha scritto:
>
>     > Respected Sir/Ma'am
>     > I was doing phonon calculation for a supercell and I encountered
>     with a
>     > problem that the calculations did not converge as the maximum
>     iteration was
>     > till 100 only.
>     > I tried changing the maxter from 100 to 300 but all in vain.
>     This all was
>     > for phonon calculation. So can you provide me with some way to
>     increase the
>     > number of iterations for phonon calculation?
>
>
>
>     GIUSEPPE MATTIOLI
>     CNR - ISTITUTO DI STRUTTURA DELLA MATERIA
>     Via Salaria Km 29,300 - C.P. 10
>     I-00015 - Monterotondo Scalo (RM)
>     Mob (*preferred*) +39 373 7305625
>     Tel + 39 06 90672342 - Fax +39 06 90672316
>     E-mail: <giuseppe.mattioli at ism.cnr.it
>     <mailto:giuseppe.mattioli at ism.cnr.it>>
>
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