Cut-off problrm

simin pahlavi simin.... at gmail.com
Tue May 1 19:47:02 UTC 2018


Hello,
Thank you very much Matheu for your answer.
Maybe I am misunderstood, but I thought we call convergence where the 
energy does not change in the accuracy range of eps_scf 10-7.
what do you mean by  1 meV per formula unit ?
Could you please clear this out?
Best regards
Simin

On Monday, April 30, 2018 at 6:47:11 PM UTC+2, Matt W wrote:
>
> Oh, come on now. Typical papers with PW codes report convergence to 1 meV 
> per formula unit or similar. I think you are quite safe! 
>
> It is a definite improvement, no?
>
> On Monday, April 30, 2018 at 2:10:45 PM UTC+1, simin pahlavi wrote:
>>
>> Dear Matheu,
>> As you guide, I changed the     XC_SMOOTH_RHO NONE     XC_DERIV PW
>> parts , and also I am asking for ngrids 1. but still I dont see a clear 
>> convergence in cuttoff.  Is it possible that there is a random number 
>> generator somewhere in my input?
>> I really appreciate any helps in advance.
>>
>>  cutoff                  energy
>>   50.0000000000  -230.8714667076           0
>>  100.0000000000  231.7994590012           0
>>  150.0000000000  -231.8316639575           0
>>  200.0000000000  -231.8369041137           0
>>  250.0000000000  -231.8375305477           0
>>  300.0000000000  -231.8377198370           0
>>  350.0000000000  -231.8375224535           0
>>  400.0000000000  -231.8375088884           0
>>  450.0000000000  -231.8375120028           0
>>  500.0000000000  -231.8375120028           0
>>  550.0000000000  -231.8375100426           0
>>  600.0000000000  -231.8375088384            0
>>
>>
>> &GLOBAL
>>  PRINT_LEVEL MEDIUM
>>   PROJECT HH
>>  RUN_TYPE ENERGY
>> # SEED 300
>> &END GLOBAL
>>
>>
>> &FORCE_EVAL
>>  METHOD Quickstep
>>  &DFT
>> #  WFN_RESTART_FILE_NAME HH
>>   BASIS_SET_FILE_NAME ../BASIS_MOLOPT
>>   POTENTIAL_FILE_NAME ../GTH_POTENTIALS
>>     CHARGE 0
>>     MULTIPLICITY 6
>>     &MGRID
>>   NGRIDS 1
>>   CUTOFF LT_cutoff
>>   REL_CUTOFF LT_rel_cutoff
>>   #     CUTOFF LT_cutoff 
>>     &END
>>    &QS
>>   #    ! use the GPW method (i.e. pseudopotential based calculations with 
>> the Gaussian and Plane Waves scheme).
>>   #    METHOD GPW 
>>   #    ! default threshold for numerics ~ roughly numerical accuracy of 
>> the total energy per electron,
>>   #    ! sets reasonable values for all other thresholds.
>>   #    EPS_DEFAULT 1.0E-10 
>>   #    ! used for MD, the method used to generate the initial guess.
>>       EXTRAPOLATION ASPC
>>       EPS_DEFAULT 1.0E-10
>> #      WF_INTERPOLATION PS
>> #      EXTRAPOLATION_ORDER 3
>>       METHOD GPW
>>     &END
>>     &POISSON
>>        PERIODIC XYZ ! 
>>     &END
>>  &SCF
>>    SCF_GUESS ATOMIC
>>    EPS_SCF 5.e-7
>>    MAX_SCF 1
>>       &OT
>>         !an accurate preconditioner suitable also for larger systems
>>         PRECONDITIONER FULL_SINGLE_INVERSE
>>         !the most robust choice (DIIS might sometimes be faster, but not 
>> as stable).
>>         MINIMIZER DIIS
>>       &END OT
>>    &OUTER_SCF
>>     TYPE NONE
>>     OPTIMIZER NONE
>>     EPS_SCF 5.0E-7
>>     MAX_SCF 1
>>    &END OUTER_SCF
>>   &END SCF
>>
>>   &XC
>>    &XC_FUNCTIONAL PBE
>>    &END XC_FUNCTIONAL
>>    &XC_GRID
>>  #   XC_SMOOTH_RHO NN50
>>  #   XC_DERIV NN50_SMOOTH
>>     XC_SMOOTH_RHO NONE
>>     XC_DERIV PW
>>
>>    &END XC_GRID
>>    &VDW_POTENTIAL
>>     DISPERSION_FUNCTIONAL PAIR_POTENTIAL
>>     &PAIR_POTENTIAL
>>      TYPE DFTD3
>>      PARAMETER_FILE_NAME ../../dftd3.dat
>>      REFERENCE_FUNCTIONAL PBE
>>      CALCULATE_C9_TERM TRUE
>>      REFERENCE_C9_TERM TRUE
>>      LONG_RANGE_CORRECTION TRUE
>>      VERBOSE_OUTPUT TRUE
>>      R_CUTOFF 15.0
>>     &END PAIR_POTENTIAL
>>    &END VDW_POTENTIAL
>>   &END XC
>>  &END DFT
>>
>>  &SUBSYS
>>   &CELL
>>    ABC 16.0 16.0 16.0
>>    PERIODIC XYZ
>>   &END CELL
>>      &TOPOLOGY
>>       COORDINATE XYZ
>>       COORD_FILE_NAME ../structure
>>       CONNECTIVITY OFF
>>    # &TOPOLOGY
>>     #  COORDINATE XYZ
>>       #COORD_FILE_NAME Fin-struct.xyz 
>>      # CONNECTIVITY OFF
>>     &END TOPOLOGY
>>  &END SUBSYS
>> &END FORCE_EVAL
>>
>>          
>>    
>>
>> On Monday, April 23, 2018 at 10:41:00 PM UTC+2, Matt W wrote:
>>>
>>> Sorry, I posted too quickly without really looking at your setup.
>>>
>>> The big problem for you is the XC_GRID settings. 
>>>
>>>    &XC_GRID
>>>     XC_SMOOTH_RHO NN50
>>>     XC_DERIV NN50_SMOOTH
>>>    &END XC_GRID
>>>
>>> You really do not want to be using heavy smoothing, especially for this 
>>> purpose. These settings (see original paper) help get reasonable forces 
>>> with a rather low cutoff, but as you increase the cutoff lead to you 
>>> continuously redefining the XC functional you use (you are smoothing over 
>>> different areas of real space), so they do not converge.
>>>
>>> Try changing to the defaults
>>>
>>>    &XC_GRID
>>>     XC_SMOOTH_RHO NONE
>>>     XC_DERIV PW
>>>    &END XC_GRID
>>>
>>> you should see at least a significant improvement.
>>>
>>> Matt
>>>
>>> On Monday, April 23, 2018 at 6:38:35 PM UTC+1, simin pahlavi wrote:
>>>>
>>>> Also for ngrid 1 the output is:
>>>> shouldn't we not see any changes less than 10e-7 in energy with 
>>>> changing cutoff?
>>>> I relay appreciate any help here
>>>>
>>>>   50.0000000000  -230.3665655634           0
>>>>  100.0000000000  -231.5201721491          0
>>>>  150.0000000000  -231.6333696011           0
>>>>  200.0000000000 -231.6954662742           0
>>>>  250.0000000000  -231.7211472374          0
>>>>  300.0000000000  -231.7441677975          0
>>>>  350.0000000000 -231.7546966069           0
>>>>  400.0000000000  -231.7608341845          0
>>>>  450.0000000000  -231.7712553463           0
>>>>  500.0000000000  -231.7712553463           0
>>>>  550.0000000000  -231.7762288308           0
>>>>  600.0000000000  -231.7833659880            0
>>>>
>>>> On Monday, April 23, 2018 at 6:55:33 PM UTC+2, simin pahlavi wrote:
>>>>>
>>>>>
>>>>> Dear Matteu,
>>>>> Thank you very much for your quick answer,
>>>>> I am not sure what did you mean by " Your set up is converged at the 
>>>>> lowest setting you report",
>>>>>  because after first few step with convergence I had a different 
>>>>> energy in next cutoffs. 
>>>>> but the result for lower cutoff is  as the following.
>>>>> Can I ask where is the suitable cutoff is now? and why you say so?
>>>>>
>>>>>  Grid cutoff vs total energy
>>>>> # Date: Mon Apr 23 18:44:42 CEST 2018
>>>>> # REL_CUTOFF = 60
>>>>> # Cutoff (Ry) | Total Energy (Ha) | NG on grid 1 | NG on grid 2 | NG 
>>>>> on grid 3 | NG on grid 4
>>>>>   50.0                   -230.3665656028      88679   13322      48    
>>>>>    0
>>>>>  100.0                  -231.5201721496       69162   25725    7162    
>>>>>    0
>>>>>  150.0                   231.6333696411       66211   22468   13322    
>>>>>   48
>>>>>  200.0                  -231.6954662441       48271   28520   25210    
>>>>>   48
>>>>>  250.0                  -231.7211472373       45554   27891   28476    
>>>>>  128
>>>>>  300.0                  -231.7441677949       43072   26090   25725    
>>>>> 7162
>>>>>  350.0                  -231.7546966111       43072   23982   22834  
>>>>>  12161
>>>>>  400.0                   -231.7608341848      40587   25752   23501  
>>>>>  12209
>>>>>  450.0                   -231.7712553838       36594   29617   22468  
>>>>>  13370
>>>>>  500.0                   -231.7712553419        31682   21399   35598  
>>>>>  13370
>>>>>  550.0                   -231.7762288293       24651   26716   28756  
>>>>>  21926
>>>>>  600.0                   -231.7833659579        24651   23620   28520  
>>>>>  25258
>>>>>
>>>>> with best regards
>>>>> Simin
>>>>>
>>>>> On Monday, April 23, 2018 at 2:57:15 PM UTC+2, Matt W wrote:
>>>>>>
>>>>>> To see really clean convergence you need to turn off multigrids (set 
>>>>>> ngrids 1).
>>>>>>
>>>>>> Your set up is converged at the lowest setting you report.
>>>>>>
>>>>>> We need a new tutorial on how to get happy pw settings.
>>>>>>
>>>>>> On Monday, April 23, 2018 at 11:38:03 AM UTC+1, simin pahlavi wrote:
>>>>>>>
>>>>>>> Dear aal,
>>>>>>> Hello. 
>>>>>>> I am trying to find a suitable cutoff for my DFT calculation on 
>>>>>>> hydrocarbons according to the cp2k manual 
>>>>>>> https://www.cp2k.org/howto:converging_cutoff. I appriciate any help 
>>>>>>> in advance.
>>>>>>> The results never converge  and the calculated output for  
>>>>>>> REL_CUTOFF = 60, is as following:
>>>>>>>   
>>>>>>> # Grid cutoff vs total energy
>>>>>>> # Date: Fri Apr 20 20:39:04 CEST 2018
>>>>>>> # REL_CUTOFF = 60
>>>>>>> # Cutoff (Ry) | Total Energy (Ha) | NG on grid 1 | NG on grid 2 | NG 
>>>>>>> on grid 3 | NG on grid 4
>>>>>>>  800.0                   -231.7994673423      73445   28476     128  
>>>>>>>      0
>>>>>>>  850.0                   -231.7994673423       73445   28476    
>>>>>>>  128       0
>>>>>>>  900.0                   -231.8023753152       69162   25725    
>>>>>>> 7162       0
>>>>>>>  950.0                   -231.8023753152       69162   25725    
>>>>>>> 7162       0
>>>>>>> 1000.0                  -231.8065368280       69162   25725    7162  
>>>>>>>      0
>>>>>>> 1050.0                  -231.8065368280       69162   25725    7162  
>>>>>>>      0
>>>>>>> 1100.0                  -231.8065368280       67054   27833    7162  
>>>>>>>      0
>>>>>>> 1150.0                  -231.8129239556        67054   22834  
>>>>>>>  12161       0
>>>>>>> 1200.0                  -231.8129239556        67054   22834  
>>>>>>>  12161       0
>>>>>>> 1250.0                  -231.8129239556        67054   22834  
>>>>>>>  12161       0
>>>>>>> 1300.0                  -231.8129239556        66339   23501  
>>>>>>>  12209       0
>>>>>>> 1350.0                  -231.8129239556        66339   23501  
>>>>>>>  12161      48
>>>>>>> 1400.0                  -231.8148206637        66259   22420  
>>>>>>>  13322      48
>>>>>>> 1450.0                  -231.8148206637       66211   22468   13322  
>>>>>>>     48
>>>>>>> 1500.0                  -231.8148206637        66211   22468  
>>>>>>>  13322      48
>>>>>>> 1550.0                  -231.8158559068        63323   25356  
>>>>>>>  13322      48
>>>>>>> 1600.0                  -231.8175292623        57217   31462  
>>>>>>>  13322      48
>>>>>>>
>>>>>>> ********************************************************************************
>>>>>>> Also my input file is :
>>>>>>>
>>>>>>> ******************************************************************************
>>>>>>> &GLOBAL
>>>>>>>  PRINT_LEVEL MEDIUM
>>>>>>> # WALLTIME 36:00:00  # changed
>>>>>>>  PROJECT cuttoff-test
>>>>>>>  RUN_TYPE ENERGY
>>>>>>>  SEED 300
>>>>>>> &END GLOBAL
>>>>>>>
>>>>>>>
>>>>>>> &FORCE_EVAL
>>>>>>>  METHOD Quickstep
>>>>>>>  &DFT
>>>>>>>   BASIS_SET_FILE_NAME ../data/BASIS_MOLOPT
>>>>>>>   POTENTIAL_FILE_NAME ../data/GTH_POTENTIALS
>>>>>>>     CHARGE 0
>>>>>>>     MULTIPLICITY 1
>>>>>>>     &MGRID
>>>>>>>   NGRIDS 4
>>>>>>>   CUTOFF LT_cutoff
>>>>>>>   REL_CUTOFF LT_rel_cutoff
>>>>>>>     &END
>>>>>>>    &QS
>>>>>>>       EPS_DEFAULT 1.0E-10
>>>>>>>       WF_INTERPOLATION PS
>>>>>>>       EXTRAPOLATION_ORDER 3
>>>>>>>       METHOD GPW
>>>>>>>     &END
>>>>>>>
>>>>>>>   &SCF
>>>>>>>    SCF_GUESS ATOMIC
>>>>>>>    EPS_SCF 5.e-7
>>>>>>>    MAX_SCF 1
>>>>>>>       &OT
>>>>>>>         MINIMIZER DIIS
>>>>>>>       &END OT
>>>>>>>    &OUTER_SCF
>>>>>>>     TYPE NONE
>>>>>>>     OPTIMIZER NONE
>>>>>>>     EPS_SCF 5.0E-7  
>>>>>>>     MAX_SCF 1
>>>>>>>    &END OUTER_SCF 
>>>>>>>   &END SCF
>>>>>>>
>>>>>>>   &XC
>>>>>>>    &XC_FUNCTIONAL PBE
>>>>>>>    &END XC_FUNCTIONAL
>>>>>>>    &XC_GRID
>>>>>>>     XC_SMOOTH_RHO NN50
>>>>>>>     XC_DERIV NN50_SMOOTH
>>>>>>>    &END XC_GRID
>>>>>>>    &VDW_POTENTIAL 
>>>>>>>     DISPERSION_FUNCTIONAL PAIR_POTENTIAL
>>>>>>>     &PAIR_POTENTIAL
>>>>>>>      TYPE DFTD3
>>>>>>>      PARAMETER_FILE_NAME ../data/dftd3.dat
>>>>>>>      REFERENCE_FUNCTIONAL PBE
>>>>>>>      CALCULATE_C9_TERM TRUE
>>>>>>>      REFERENCE_C9_TERM TRUE
>>>>>>>      LONG_RANGE_CORRECTION TRUE
>>>>>>>      VERBOSE_OUTPUT TRUE
>>>>>>>      R_CUTOFF 15.0
>>>>>>>     &END PAIR_POTENTIAL 
>>>>>>>    &END VDW_POTENTIAL
>>>>>>>   &END XC
>>>>>>>  &END DFT
>>>>>>>
>>>>>>>  &SUBSYS
>>>>>>>   &CELL
>>>>>>>    ABC 16.0 16.0 16.0
>>>>>>>    PERIODIC XYZ
>>>>>>>   &END CELL
>>>>>>>
>>>>>>>     &KIND H
>>>>>>>       BASIS_SET DZVP-MOLOPT-SR-GTH-q1
>>>>>>>       POTENTIAL GTH-PBE-q1
>>>>>>>     &END
>>>>>>>
>>>>>>>     &KIND C
>>>>>>>       BASIS_SET DZVP-MOLOPT-SR-GTH-q4
>>>>>>>      POTENTIAL GTH-PBE-q4
>>>>>>>     &END KIND
>>>>>>>
>>>>>>>
>>>>>>>     &TOPOLOGY
>>>>>>>       COORDINATE XYZ
>>>>>>>       COORD_FILE_NAME ../data/structure 
>>>>>>>       CONNECTIVITY OFF
>>>>>>>     &END TOPOLOGY
>>>>>>>  &END SUBSYS
>>>>>>> &END FORCE_EVAL
>>>>>>>
>>>>>>>
>>>>>>>
>>>>>>>
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <https://lists.cp2k.org/archives/cp2k-user/attachments/20180501/1b48d208/attachment.htm>


More information about the CP2K-user mailing list