[CP2K:701] convergence issues with rCAM-B3LYP

Fawzi Mohamed fa... at gmx.ch
Thu Feb 21 18:01:24 CET 2008


Hi rad,

The cutoff is definitely high enough, also lower (280) should work.
One thing that you might what to change is
&XC
   &XC_GRID
     XC_DERIV spline3
   &END
&END
which should be marginally better.

What is your cell? Is the system periodic? If not I suspect that the  
error is there, the cell must be at least twice the size of your  
system (with electrons, not just ions).

For parallel code with non orthorombic cell I had found a bug that  
Joost fixed just after you compiled:
Feb 14 16:20:19 2008
If you are running in parallel and your cell is not orthormbit it is  
most likely the reason of your problems.

ciao
Fawzi
On Feb 21, 2008, at 3:12 PM, Rad wrote:

>
> Dear All,
>
> I managed to compile cp2k (Last CVS entry               qs_scf_post.F/
> 1.149/Wed Feb 13 23:07:05 2008) with libint (thaks to Teo's
> suggestions) and tested the sample input that uses rCAM-B3LYP. This
> input file was set up to do a single point energy calculation. I
> adopted the same input file for my system with just 56 atoms and tried
> a simple geometry optimization. The wave function is not converging at
> all (at most I got two convergences of the outer loop). Here is the
> input section I used:
> &FORCE_EVAL
>   METHOD Quickstep
>   &DFT
>     BASIS_SET_FILE_NAME EMSL_BASIS_SETS
>     POTENTIAL_FILE_NAME POTENTIAL
>     &MGRID
>       CUTOFF 1600
>       NGRIDS  5
>       REL_CUTOFF 50
>     &END MGRID
>     &QS
>       METHOD GAPW
>       MAP_CONSISTENT
>        EXTRAPOLATION PS
>        EXTRAPOLATION_ORDER 2
>     &END QS
>     &SCF
>       &OT on
>        MINIMIZER  DIIS
>        PRECONDITIONER FULL_SINGLE_INVERSE
>        STEPSIZE 0.05
>       &END OT
>       &OUTER_SCF
>          EPS_SCF 1.0E-6
>          MAX_SCF 40
>       &END OUTER_SCF
>       EPS_SCF 1.0E-6
>       SCF_GUESS RESTART
>       MAX_SCF 500
>     &END SCF
>     &XC
>       &XC_FUNCTIONAL
>         &BECKE88
>           SCALE_X 0.95238
>         &END
>         &BECKE88_LR
>           OMEGA 0.33
>           SCALE_X -0.94979
>         &END
>         &LYP
>           SCALE_C 1.0
>         &END
>         &XALPHA
>           SCALE_X -0.13590
>         &END
>       &END XC_FUNCTIONAL
>       &HF
>        &SCREENING
>          EPS_SCHWARZ 1.0E-10
>          EPS_BOX 1.0E-10
>        &END
>        &MEMORY
>          MAX_MEMORY 100
>        &END
>        &INTERACTION_POTENTIAL
>          POTENTIAL_TYPE MIX_CL
>          OMEGA 0.33
>          SCALE_LONGRANGE 0.94979
>          SCALE_COULOMB 0.18352
>        &END
>       &END
>     &END XC
>   &END DFT
>
> Could you please take a look at it and offer me suggestions to tweak
> the parametrs for wavefunction convegence.
> I also tried CG with different step sizes in the OT section and also a
> run without OT section but still no convergence at all. I will
> appreciate any suggestions/pointers you may offer in this regard.
>
> Thanks
> Rad
> 



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