[CP2K-user] [CP2K:16432] Re: Cell Optimization of Platinum (Pt) with fcc (111) surface

GENG YUAN yuangeng0821 at gmail.com
Wed Jan 5 21:25:18 UTC 2022


Dear Lucas,

Many thanks for your information. I didn't notice that the EPS_SCF value 
under &OUTER_SCF section was still the old value, I will change it the same 
as the EPS_SCF value under &SCF section.

I will also try to run another test using EPS_DEFAULT 1e-16 to see how the 
performance looks like.

Sincerely - Geng

在2022年1月5日星期三 UTC-5 16:00:28<Lucas Lodeiro> 写道:

> Hi, 
>
> I usually set the same EPS_SCF value at the SCF and OUTER_SCF section. 
> Also, I read somewhere (I do not remember), EPS_SCF cannot be less than the 
> square root of EPS_DEFAULT. I guess EPS_DEFAULT 1E-16 and EPS_SCF 1E-8 
> could converge with less cycles, but the time amount per cycle will be 
> higher.
>
> regards - Lucas
>
> El mié, 5 ene 2022 a las 17:49, GENG YUAN (<yuange... at gmail.com>) 
> escribió:
>
>> Dear Fabian,
>>
>> Many thanks for your advice!
>> I decrease eps_scf (under &SCF section) to 1e-8 (the old setting is 1e-6) 
>> and found that this didn't improve the convergence of the cell 
>> optimization. It took 433 steps to converge, and the overall simulation 
>> running time also increased.
>>
>> Attached are the new input, output, and trajectory for your reference. 
>>
>> Please let me know if any thoughts.
>> Sincerely,
>> Geng
>>
>> 在2022年1月3日星期一 UTC-5 16:03:37<fabia... at gmail.com> 写道:
>>
>>> Dear Geng,
>>>
>>> You should decrease eps_scf to 1e-7 or 1e-8. The default 1e-6 is good 
>>> for the initial stage of the optimization, when the forces/pressure are 
>>> still large. Later on this should be adjusted, especially if you request 
>>> such tight convergence criteria in &CELL_opt. Decreasing this value reduces 
>>> the noise in the forces and improves the convergence of the cell 
>>> optimization.
>>>
>>> Cheers,
>>>
>>> Fabian
>>>
>>> On 03.01.2022 21:40, GENG YUAN wrote:
>>>
>>> Here are the screenshots. 
>>> [image: beforecellopt_view1.png][image: aftercellopt_view1.png]
>>> Top view before cell optimization                                        
>>>                                   Top view after cell optimization
>>>
>>> [image: beforecellopt_view2.png][image: aftercellopt_view2.png]
>>> Another view before cell optimization                                    
>>>                                Another view after cell optimization
>>>
>>> Sincerely,
>>> Geng
>>>
>>> 在2022年1月3日星期一 UTC-5 15:34:56<GENG YUAN> 写道:
>>>
>>>> Dear CP2K Users, 
>>>>
>>>> Hope you are going great and happy new year.
>>>>
>>>> I am running the cell optimization for a single bulk Pt (134 atoms) 
>>>> with fcc 111 surface. By checking my output file, I notice that the cell 
>>>> optimization takes 446 steps to converge (which is almost close to the 
>>>> maximum number of optimization steps:500). Besides, a certain degree of 
>>>> structure deformation is observed during optimization (please see the 
>>>> attached files and screenshots).
>>>>
>>>> I am wondering if there are any other ways to let the cell optimization 
>>>> converge faster (in other words, converge in fewer steps) and whether the 
>>>> above-mentioned deformation looks reasonable?
>>>> Below is the input: (attached are input file, output file, original 
>>>> coordinate, trajectory, and the screenshots of the trajectory)
>>>> ------------------------------------------------------------
>>>> &GLOBAL
>>>>   PROJECT Pt_cellopt
>>>>   RUN_TYPE CELL_OPT
>>>>   PRINT_LEVEL LOW
>>>> &END GLOBAL
>>>> &FORCE_EVAL
>>>>   METHOD QS
>>>>   STRESS_TENSOR ANALYTICAL
>>>>   &SUBSYS
>>>>     &CELL
>>>>       ABC 13.7 13.7 13.7
>>>>       SYMMETRY CUBIC
>>>>      &CELL_REF
>>>>       ABC 13.7*1.5 13.7*1.5 13.7*1.5
>>>>      &END 
>>>>     &END CELL
>>>>     &TOPOLOGY
>>>>      COORD_FILE_NAME ./Pt134.xyz
>>>>      COORDINATE xyz
>>>>     &END
>>>>     &KIND Pt
>>>>       BASIS_SET DZVP-MOLOPT-SR-GTH
>>>>       POTENTIAL GTH-PBE-q18
>>>>     &END KIND
>>>>   &END SUBSYS
>>>>   &DFT
>>>>     BASIS_SET_FILE_NAME ./BASIS_MOLOPT
>>>>     POTENTIAL_FILE_NAME ./GTH_POTENTIALS
>>>>     &QS
>>>>       EPS_DEFAULT 1.0E-12
>>>>     &END QS
>>>>     &MGRID
>>>>       CUTOFF 400
>>>>       NGRIDS 5
>>>>       REL_CUTOFF 40
>>>>     &END MGRID
>>>>     &SCF
>>>>       SCF_GUESS ATOMIC
>>>>       EPS_SCF 1.0E-06
>>>>       MAX_SCF 200
>>>>       ADDED_MOS 100
>>>>       &OUTER_SCF
>>>>         MAX_SCF 50
>>>>         EPS_SCF 1.0E-6
>>>>       &END
>>>>       &DIAGONALIZATION T
>>>>         ALGORITHM STANDARD
>>>>       &END DIAGONALIZATION
>>>>       &MIXING T
>>>>         METHOD BROYDEN_MIXING
>>>>         ALPHA 0.1
>>>>         NBROYDEN 8
>>>>       &END MIXING
>>>>       &SMEAR ON
>>>>         METHOD FERMI_DIRAC
>>>>         ELECTRONIC_TEMPERATURE [K] 500
>>>>       &END SMEAR
>>>>       &PRINT
>>>>         &RESTART ON
>>>>         &END RESTART
>>>>       &END PRINT
>>>>     &END SCF
>>>>     &XC
>>>>       &XC_FUNCTIONAL
>>>>          &LIBXC
>>>>            FUNCTIONAL XC_GGA_X_PBE_R
>>>>          &END
>>>>          &LIBXC
>>>>            FUNCTIONAL XC_GGA_C_PBE
>>>>          &END
>>>>       &END XC_FUNCTIONAL
>>>>       &VDW_POTENTIAL
>>>>          POTENTIAL_TYPE PAIR_POTENTIAL
>>>>          &PAIR_POTENTIAL
>>>>             LONG_RANGE_CORRECTION
>>>>             PARAMETER_FILE_NAME dftd3.dat
>>>>             TYPE DFTD3
>>>>             REFERENCE_FUNCTIONAL revPBE
>>>>          &END PAIR_POTENTIAL
>>>>        &END VDW_POTENTIAL
>>>>        &XC_GRID
>>>>         XC_DERIV NN50_SMOOTH
>>>>        &END XC_GRID
>>>>     &END XC
>>>>   &END DFT
>>>> &END FORCE_EVAL
>>>> &MOTION
>>>>   &CELL_OPT
>>>>     EXTERNAL_PRESSURE 0
>>>>     TYPE DIRECT_CELL_OPT
>>>>     KEEP_SYMMETRY TRUE
>>>>     MAX_DR    1.0E-05
>>>>     MAX_FORCE 1.0E-05
>>>>     RMS_DR    1.0E-05    
>>>>     RMS_FORCE 1.0E-05
>>>>     MAX_ITER 500
>>>>     OPTIMIZER BFGS
>>>>   &END CELL_OPT
>>>> &END MOTION 
>>>>
>>>> Many thanks in advance,
>>>> Sincerely,
>>>> Geng
>>>>
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