[QE-users] Convergence and restart of hp.x

Prasenjit Ghosh prasenjit.jnc at gmail.com
Mon Aug 17 11:38:44 CEST 2020


Dear Iurii,

Thanks for your response.

>
> For the HP calculation you can try alpha_mix(1)=0.1 or even 0.05. Also
> try to use niter_max = 200 or 300.
>
I have submitted one calculation with niter_max=300. It is running. Let's
see what happens.


>
> For the SCF calculation degauss=0.004 Ry is very small. The system is
> gapped or metallic at the PBE level? Maybe you can try larger values for
> degauss? Also you can try higher values for ecutwfc and ecutrho.
>
>
> It is metallic at PBE level and it is expected to be so. The actual system
that I am interested in is a composite of this one with another material.
However, that involves a larger unit cell. So I thought that it would be
best to do it with this smaller one and understand the method before going
to a larger system.


> > When I go to higher k-mesh, some of the k-points are not converging
> (within 100 iterations).
>
>
> Do you mean some q points that do not converge?
>
>
> Yes. For my system with 2x2x2 q-grid I get the following q-points:


       1   0.000000000   0.000000000   0.000000000   0.125000000
       2   0.000000000   0.000000000  -0.500000000   0.375000000
       3   0.000000000  -0.500000000  -0.500000000   0.375000000
       4  -0.500000000  -0.500000000  -0.500000000   0.125000000
The hp.x calculation converged for all the q-points.

Using a 3x3x3 q-grid, I am getting the following q-points:

       1   0.000000000   0.000000000   0.000000000   0.037037037
       2   0.000000000   0.000000000   0.333333333   0.222222222
       3   0.000000000   0.333333333   0.333333333   0.444444444
       4   0.333333333   0.333333333   0.333333333   0.296296296

So at q=(0,0,0) and q=(0,0.1/3), the calculation converged. However, for
the third one it is not converging.

Let me try with your suggestions and see if I can make the calculations
converge. I will keep you posted.


With regards,
Prasenjit


> Greetings,
>
> Iurii
>
>
> --
> Dr. Iurii Timrov
> Postdoctoral Researcher
> STI - IMX - THEOS and NCCR - MARVEL
> Swiss Federal Institute of Technology Lausanne (EPFL)
> CH-1015 Lausanne, Switzerland
> +41 21 69 34 881
> http://people.epfl.ch/265334
> ------------------------------
> *From:* users <users-bounces at lists.quantum-espresso.org> on behalf of
> Prasenjit Ghosh <prasenjit.jnc at gmail.com>
> *Sent:* Monday, August 17, 2020 10:57:41 AM
> *To:* Quantum ESPRESSO users Forum
> *Subject:* Re: [QE-users] Convergence and restart of hp.x
>
> Dear Iurii,
>
> Thanks for your prompt response. I would just like to point out that the
> calculation is converging for a smaller q-mesh, 2x2x2 in my case. When I go
> to higher k-mesh, some of the k-points are not converging (within 100
> iterations). I have not yet tried increasing the no. of iterations.
>
> Given below is the input scf file:
>
> &control
>     calculation = 'scf'
>     restart_mode='from_scratch',
>     prefix='tifesb',
>     pseudo_dir = './',
>     outdir= './tmp_tifesb'
>
>  /
>  &system
>     ibrav= 1, celldm(1)= 11.343477089,
>      nat=12, ntyp= 3,
>     ecutwfc = 60, ecutrho=500,
>    occupations='smearing'
>    smearing='mv'
>    degauss=0.004
>    lda_plus_u=.true.
>    lda_plus_u_kind=0
>    U_projection_type='atomic'
>    Hubbard_U(2)=1.0d-10
>    Hubbard_U(3)=1.0d-10
>  /
>  &electrons
>     diagonalization='david'
>     mixing_mode = 'local-TF'
>     mixing_beta = 0.3
>     conv_thr =  1.0d-07
>  /
> &ions
> /
> &cell
> cell_dofree='xyz'
> /
> ATOMIC_SPECIES
> Sb 50.9415    Sb.pbe-n-rrkjus_psl.1.0.0.UPF
> Fe 26.981539  Fe.pbe-sp-van_mit.UPF
> Ti 26.981539  Ti.pbe-spn-rrkjus_psl.1.0.0.UPF
>
> ATOMIC_POSITIONS (crystal)
> Ti   0.000000000    0.000000000    0.000000000
> Ti   0.500000000    0.500000000    0.000000000
> Ti   0.000000000    0.500000000    0.500000000
> Ti   0.500000000    0.000000000    0.500000000
> Fe   0.250000000    0.250000000    0.250000000
> Fe   0.750000000    0.750000000    0.250000000
> Fe   0.250000000    0.750000000    0.750000000
> Fe   0.750000000    0.250000000    0.750000000
> Sb   0.500000000    0.500000000    0.500000000
> Sb   1.000000000    1.000000000    0.500000000
> Sb   0.500000000    1.000000000    1.000000000
> Sb   1.000000000    0.500000000    1.000000000
> K_POINTS {automatic}
> 12 12 12 1 1 1
>
> The input for the hp.x is given below:
>
> &inputhp
> prefix='tifesb'
> outdir='./tmp_tifesb'
> nq1=3, nq2=3, nq3=3
> conv_thr_chi = 1.0d-5
> iverbosity = 2
> alpha_mix(1)=0.2
> /
>
> With regards,
> Prasenjit
>
> On Mon, 17 Aug 2020 at 13:58, Timrov Iurii <iurii.timrov at epfl.ch> wrote:
>
>> Dear Prasenjit Ghosh,
>>
>>
>> > Can someone please indicate other input parameters that can be tuned to
>> reach convergence?
>>
>> You can check the HP documentation, but there are not that many
>> parameters that can help to converge the HP calculation. Typically, the
>> reason why HP does not converge is because there are problems with the SCF
>> calculation. Can you share with us your input files for PWscf and HP? This
>> will help us to understand what can be the problem.
>>
>> > Also is there a way to restart the hp.x calculations?
>>
>>
>> Yes. Check examples 7 in the HP repository. You can restart from a q
>> point which was not converged (note that for this q point the calculation
>> will be done from scratch).
>>
>>
>> Greetings,
>>
>> Iurii
>>
>>
>> --
>> Dr. Iurii Timrov
>> Postdoctoral Researcher
>> STI - IMX - THEOS and NCCR - MARVEL
>> Swiss Federal Institute of Technology Lausanne (EPFL)
>> CH-1015 Lausanne, Switzerland
>> +41 21 69 34 881
>> http://people.epfl.ch/265334
>> ------------------------------
>> *From:* users <users-bounces at lists.quantum-espresso.org> on behalf of
>> Prasenjit Ghosh <prasenjit.jnc at gmail.com>
>> *Sent:* Monday, August 17, 2020 5:10:56 AM
>> *To:* Quantum Espresso users Forum
>> *Subject:* [QE-users] Convergence and restart of hp.x
>>
>> Dear all,
>>
>> I am using hp.x to compute the U value. I have two types of Hubbard atoms
>> in my unit cell. I am using qe-6.5.
>> For my system with a 2x2x2 q-grid, the calculations converge. However,
>> the moment I use a denser grid, the calculations don't converge, even after
>> playing around with the mixing parameter.
>>
>> Can someone please indicate other input parameters that can be tuned to
>> reach convergence?
>> Also is there a way to restart the hp.x calculations?
>>
>> With regards,
>> Prasenjit
>>
>> --
>> PRASENJIT GHOSH,
>> IISER Pune,
>> Dr. Homi Bhabha Road, Pashan
>> Pune, Maharashtra 411008, India
>>
>> Phone: +91 (20) 2590 8203
>> Fax: +91 (20) 2589 9790
>> _______________________________________________
>> Quantum ESPRESSO is supported by MaX (www.max-centre.eu/quantum-espresso)
>> users mailing list users at lists.quantum-espresso.org
>> https://lists.quantum-espresso.org/mailman/listinfo/users
>
>
>
> --
> PRASENJIT GHOSH,
> IISER Pune,
> Dr. Homi Bhabha Road, Pashan
> Pune, Maharashtra 411008, India
>
> Phone: +91 (20) 2590 8203
> Fax: +91 (20) 2589 9790
> _______________________________________________
> Quantum ESPRESSO is supported by MaX (www.max-centre.eu/quantum-espresso)
> users mailing list users at lists.quantum-espresso.org
> https://lists.quantum-espresso.org/mailman/listinfo/users



-- 
PRASENJIT GHOSH,
IISER Pune,
Dr. Homi Bhabha Road, Pashan
Pune, Maharashtra 411008, India

Phone: +91 (20) 2590 8203
Fax: +91 (20) 2589 9790
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