Cut-off problrm

Matt W mattwa... at gmail.com
Mon Apr 30 18:47:11 CEST 2018


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
>>>>>>
>>>>>>
>>>>>>
>>>>>>
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