[CP2K:1929] QMMM: MM SPLINE: no convergence

[Laino Teodoro]

Dear Peter,

what you see is the right behavior. On the spline it is mapped part  
of the FF (this means LJ or other similar
potential + real-space part of coulomb).
Since some of the above interactions are zeroed in the FF for QM-MM  
runs it is highly possible that some splines
may have different behavior (different boundaries or different  
convergence).

Keep in mind that you are using the default E_COUPL, which is the  
mechanical coupling (the electrostatic QM-MM
coupling is done at the level of classical forcefield).

Cheers,
Teo

On 21 Mar 2009, at 21:38, Peter wrote:

>
> Dear all,
>
> I'm trying to setup qm/mm calculations of a test system. MM treatment
> of a system using FIST works fine. However, QM/MM calculation fails
> with the following message:
>
>  *** 22:36:04 ERRORL2 in pair_potential:generate_spline_low
> processor       ***
>  *** 0  err=-300  SPLINE_INFO| Number of points:  2346797
> obtained          ***
>  *** accuracy 0.195114E-06. MM SPLINE: no convergence on required
> accuracy  ***
>  *** (adjust EPS_SPLINE and rerun) pair_potential.F line
> 551             ***
>
> Adjusting EPS_SPLINE and/or R0_NB, EMAX_SPLINE solves the problem.
> However I found this situation quite strange, since MM calculations
> using the same FF and coordinates don't need such adjustments. Also
> I've noticed, that during QMMM run spline generator uses much wider
> boundaries (RMIN, RMAX) for some pairs, compared to MM run.
>
> So, is it the supposed behavior of the program? And if so, could you
> comment on it, please?
>
> Thanks,
> Peter
>
> Input and log files: http://groups.google.com/group/cp2k/web/ 
> mm_spline-no_convergence.tar.gz
>
> # u10-qmmm.inp:
> &GLOBAL
>   PROJECT U10-QMMM_OPT
>   RUN_TYPE GEO_OPT
>   PREFERRED_FFT_LIBRARY FFTMKL
> &END GLOBAL
>
> &MOTION
>   &GEO_OPT
>     TYPE MINIMIZATION
>     MAX_ITER 10000
>     OPTIMIZER LBFGS
>     MAX_FORCE 5.0E-4
>     RMS_FORCE 2.0E-4
>     &LBFGS
>       MAX_H_RANK 10
>       MAX_F_PER_ITER 100
>     &END LBFGS
>   &END GEO_OPT
>
>   &PRINT
>     &RESTART OFF
>     &END RESTART
>     &RESTART_HISTORY OFF
>     &END RESTART_HISTORY
>     &TRAJECTORY
>       FORMAT XYZ
>       FILENAME =u10-qmmm.xyz
>     &END TRAJECTORY
>   &END PRINT
> &END MOTION
>
> &FORCE_EVAL
>   METHOD QMMM
>
>   &DFT
>     CHARGE 0
>     MULTIPLICITY 1
>     BASIS_SET_FILE_NAME EMSL_BASIS_SETS
>     POTENTIAL_FILE_NAME POTENTIAL
>
>     &MGRID
>       CUTOFF 250
>       COMMENSURATE
>     &END MGRID
>
>     &QS
>       METHOD GAPW
>     &END QS
>
>     &SCF
>       SCF_GUESS ATOMIC
>       EPS_SCF 1.0E-6
>       MAX_SCF 150
>     &END SCF
>
>     &XC
> #These are the coefficients used for B3LYP using VWN5, this is
> recommended but doesn't match the default Gaussian definition
>       &XC_FUNCTIONAL
>        &LYP
>          SCALE_C 0.81
>        &END
>        &BECKE88
>          SCALE_X 0.72
>        &END
>        &VWN
>          FUNCTIONAL_TYPE VWN5
>          SCALE_C 0.19
>        &END
>        &XALPHA
>          SCALE_X 0.08
>        &END
>       &END XC_FUNCTIONAL
>       &HF
>         &SCREENING
>           EPS_SCHWARZ 1.0E-10
>         &END
>         &MEMORY
>           MAX_MEMORY  5
>         &END
>         FRACTION 0.20
>       &END
>     &END XC
>
>     &POISSON
>       PERIODIC NONE
>       POISSON_SOLVER WAVELET
>     &END POISSON
>   &END DFT
>
>
>   &MM
>     &FORCEFIELD
>       PARM_FILE_NAME par_all27_prot_lipid.prm
>       PARMTYPE CHM
>       &SPLINE
>         RCUT_NB 50.0
> #        UNIQUE_SPLINE T
> #        EPS_SPLINE 1.0E-12
> #        EMAX_SPLINE 0.02
> #        R0_NB = 0.45
>       &END SPLINE
>     &END FORCEFIELD
>
>     &POISSON
>       PERIODIC NONE
>       &EWALD
>         EWALD_TYPE NONE
>       &END EWALD
>     &END POISSON
>
>     &NEIGHBOR_LISTS
>       GEO_CHECK F
>     &END NEIGHBOR_LISTS
>
>     &PRINT
>       &FF_INFO
>       &END FF_INFO
>     &END PRINT
>   &END MM
>
>   &QMMM
>     &CELL
>       ABC 15.0 15.0 15.0
>     &END CELL
>
>     &QM_KIND H
>       MM_INDEX 14 15 16 17 18 19 20 21 22 28 29
>     &END QM_KIND
>
>     &QM_KIND C
>       MM_INDEX 1 2 3 4 5 6 7 8 9 23
>     &END QM_KIND
>
>     &QM_KIND O
>       MM_INDEX 10 11 12 13
>     &END QM_KIND
>
>     &LINK
>       QM_INDEX 23
>       MM_INDEX 24
>       QM_KIND H
>     &END LINK
>
>   &END QMMM
>
>   &SUBSYS
>     &CELL
>       ABC 50.0 50.0 50.0
>       PERIODIC NONE
>     &END CELL
>
>     &TOPOLOGY
>       COORD_FILE_NAME u10.pdb
>       COORD_FILE_FORMAT PDB
>       CONN_FILE_NAME u10.psf
>       CONN_FILE_FORMAT PSF
>       CENTER_COORDINATES
>     &END TOPOLOGY
>
>     &KIND O
>       BASIS_SET 6-31G*
>       POTENTIAL ALL
>     &END KIND
>
>     &KIND C
>       BASIS_SET 6-31G*
>       POTENTIAL ALL
>     &END KIND
>
>     &KIND H
>       BASIS_SET 6-31G*
>       POTENTIAL ALL
>     &END KIND
>   &END SUBSYS
> &END FORCE_EVAL
> >