Cut-off problrm

[Matt W]

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
>> # PWD: /u/nsaf/JOBS/Ad-Ml.1/Cutoff-test
>> # 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
>>>> # PWD: /u/nsaf/JOBS/Ad-Ml.1/Cutoff-test
>>>> # 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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