[Pw_forum] Fwd: pwscf: energy convergence of noncollinear with spin-orbit calculations, withdraw question

[Gabriele Sclauzero]

In the first message you were speaking about fixing the total magnetization, here you do something different. Anyway I'm happy for you that you could converge the calculations. 
It's a bit curious that you get converge only with nosym=true. What is the symmetry found by the code at the beginning of the run?

Il giorno 13/giu/2011, alle ore 21.39, German Samolyuk ha scritto:

> Hello Gabriele,
> 
> Thank you for your response and advices.
> 
> I used version 4.2.1
> 
> the actual (final) input contains instructions:
> 
> for magnetization along z-direction
> 
> starting_magnetization(1) = 0.1,
> starting_magnetization(2) = 0.4,
>          noncolin = .true. ,
>         angle1(1) = 0,
>         angle1(2) = 0,
>         angle2(1) = 0,
>         angle2(2) = 0,
>          lspinorb = .true. ,
>   constrained_magnetization = 'atomic direction' ,
>            lambda = 0.3,
>            nosym = .true.,
> 
> and magnetization perpendicular to z-direction
> 
> starting_magnetization(1) = 0.1,
> starting_magnetization(2) = 0.4,
>          noncolin = .true. ,
>         angle1(1) = 90,
>         angle1(2) = 90,
>         angle2(1) = 0,
>         angle2(2) = 0,
>          lspinorb = .true. ,
>   constrained_magnetization = 'atomic direction' ,
>            lambda = 0.3,
>            nosym = .true.,
> 
> the resulting energies  looks reasonable and convergence is really fast.

The constraint (penalty) energy should be almost zero at convergence. Could you obtain that with such a small lambda?


Regards,

Gabriele


> 
> Thank you for advice with degauss value. I'll check dependence from it.
> 
> Best,
> 
> German
> 
> 
> On Wed, Jun 8, 2011 at 3:55 AM, Gabriele Sclauzero <sclauzer at sissa.it> wrote:
>> Hello German,
>> Il giorno 01/giu/2011, alle ore 23.02, German Samolyuk ha scritto:
>> 
>> I withdraw my question. It works with nosym=true.
>> German
>> 
>> 
>> ---------- Forwarded message ----------
>> From: German Samolyuk <samolyuk at gmail.com>
>> Date: Wed, May 18, 2011 at 10:25 AM
>> Subject: pwscf: energy convergence of noncollinear with spin-orbit
>> calculations
>> To: PWSCF Forum <pw_forum at pwscf.org>
>> 
>> 
>> Dear qe users,
>> 
>> I'm trying to calculate total energy of artificial FCC PtFe compound
>> with magnetic moment (MM) along z- and x-directionsi (MAE).
>> 
>> In order to supress oscillation of moment direction I used for MM||z
>> calculation
>> input instructions
>> 
>>  constrained_magnetization = 'total direction' ,
>>   fixed_magnetization(1) = 0.0,
>>   fixed_magnetization(2) = 0.0,
>>   fixed_magnetization(3) = 1.0,
>> 
>> 
>> If it is v.>4.2, then a
>> Are you sure that this is what you want?
>> From the Doc/INPUT_PW:
>>                    'total direction':
>>                              the angle theta of the total magnetization
>>                              with the z axis (theta =
>> fixed_magnetization(3))
>>                              is constrained:
>> 
>>                              LAMBDA * ( arccos(magnetization(3)/mag_tot) -
>> theta )**2
>> 
>>                              where mag_tot is the modulus of the total
>> magnetization.
>> Then fixed_magnetization(3) = 1.0 does not correspond to the magnetization
>> along the z axis (but you should reach the corresponding constrained
>> solution anyway, even if different from what you actually want).
>> Can you please specify which version of the code you've been using?
>> Could you try to compare v.4.1.1 with v.4.3.1 (using the correct value for
>> theta=fixed_magnetization(3))
>> The constraining potential implemented is different: in the most recent
>> version it should work also for theta=90° (magnetization along x), while in
>> the previous you could get into troubles, since it was defined as:
>>                              LAMBDA * ( magnetization(1) -
>> magnetization(3)*tan(theta) )**2
>> 
>> Also convergency should be better in the 4.3.1, though I'm not sure of that.
>> You should try to start with local magnetizations on Pt and Fe close to the
>> desired target direction. It would be nice if you perform this test.
>> Also, reporting only the total energy oscillations is not that useful. You
>> should at least report the magnitude and angles of the total magnetization
>> while the calculation is going.
>> Further advice: from your input, perhaps degauss=0.02 is not enough to get
>> accurate magnetizations. I would use at least 0.01, better 0.005.
>> 
>> HTH
>> 
>> GS
>> 
>> However I can not reach total energy convergence and it looks like I
>> still have direction oscillation of MM.
>> 
>> What can be done to resolve this problem?
>> 
>> Thank you in advance.
>> 
>> The complete input file for MM||z is and energy accuracy output file
>> are attached.
>> 
>> German Samolyuk,
>> ORNL, USA
>> <ptfe.pw.in><accu.out>_______________________________________________
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>> 
>> 
>> § Gabriele Sclauzero, EPFL SB ITP CSEA
>>    PH H2 462, Station 3, CH-1015 Lausanne
>> 
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>> 
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§ Gabriele Sclauzero, EPFL SB ITP CSEA
   PH H2 462, Station 3, CH-1015 Lausanne

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