[CP2K-user] Increasing trend and discontinuity after restart in Lagrange multipliers file *-1.LagrangeMultLog

[Alejandro Ramos]

Dear all,

I'm performing a constrained MD simulation where I have constrained 10 
distances. The simulation is long so I have broken the simulation in parts 
of 100000 steps each, each time using the previous *-1.restart file as a 
starting point. 

The problem is that every time I restart the simulation I see an obvious 
discontinuity in the *-1.LagrangeMultLog file. This discontinuity is 
observed every 600000 lines in the  *-1.LagrangeMultLog file as shown by 
the red arrow in the three examples pictures attached corresponding to 
lines 600000, 1200000 and 1800000. This discontinuity is not observed in 
the trajectory file or any other file. 

Moreover, ignoring the fact that I could have some problem in how I restart 
the simulation, you can see an obvious trend for the lagrange multipliers 
to increase within each restart calculation. This increase is also not 
justified by any other file outputted by cp2k.

It appears to me some kind of cumulative error within the calculation of 
the lagrange multipliers. Any ideas of why could this be, or how to solve 
it?

Best regards,

Alejandro.


PD: My input file looks like this:


                                           

@SET basis TZV2P-GTH
@SET aux_basis cFIT3

 
@SET n_steps 100000
@SET ABC 20
@SET project_name 30_r20_ts_p_80_rep_equi_5_atm_cons_pmf
@SET rest_file 30_r20_ts_p_80_rep_equi_5_atm_cons_pmf-1.restart
@SET LIBPATH /cluster/physics/CP2K/6.0/data
@SET sys 30_r20_ts_p_80_rep
@SET natm 33
@SET job md
@SET i 5

  &GLOBAL
        PRINT_LEVEL  LOW
        PROJECT_NAME $project_name
        RUN_TYPE  $job
  &END GLOBAL

  @IF ($i /= 1)
     &EXT_RESTART
           RESTART_FILE_NAME $rest_file
     &END EXT_RESTART
  @ENDIF 
                                                              
 
&MOTION
      &MD
         ENSEMBLE NVT
         STEPS $n_steps
         TIMESTEP 0.5
         TEMPERATURE 298

         ANGVEL_TOL 1
         ANGVEL_ZERO TRUE

@IF ($i == 1)
         STEP_START_VAL 0
         TIME_START_VAL 0
@ENDIF

         &THERMOSTAT
             TYPE NOSE
             REGION GLOBAL
             &NOSE
                 TIMECON 100
             &END NOSE
         &END THERMOSTAT
      &END MD

      &PRINT
           &TRAJECTORY
              &EACH
                   MD 10
              &END
           &END

           &RESTART                                    
                 &EACH    
                          MD $n_steps
                 &END
           &END
           &RESTART_HISTORY                            
              &EACH                  
                          MD $n_steps
              &END
          &END

&END
        

       &CONSTRAINT

                @INCLUDE collective.inp
                
                &LAGRANGE_MULTIPLIERS
                    COMMON_ITERATION_LEVELS 1
                &END LAGRANGE_MULTIPLIERS
       &END  CONSTRAINT
         
&END MOTION


 &FORCE_EVAL
   METHOD  QS
    

   &DFT
      BASIS_SET_FILE_NAME  ${LIBPATH}/BASIS_MOLOPT
      POTENTIAL_FILE_NAME  ${LIBPATH}/GTH_POTENTIALS
      WFN_RESTART_FILE_NAME ${project_name}-RESTART.wfn
      
    &MGRID
      NGRIDS 5
      CUTOFF 400
      REL_CUTOFF 60
      COMMENSURATE
    &END MGRID
    
    &POISSON
            PERIODIC NONE
            POISSON_SOLVER WAVELET
    &END POISSON

 &QS
      EPS_DEFAULT 1.0E-10
      EXTRAPOLATION ASPC
      EXTRAPOLATION_ORDER 3
      EPS_PGF_ORB 1.0E-12
      METHOD DFTB
            &DFTB
                   SELF_CONSISTENT    T
                   DISPERSION  T
                   DO_EWALD           F
                   HB_SR_GAMMA        T
                   &PARAMETER
                        PARAM_FILE_PATH  /users/ar612/data_base/dftb/3ob-3-1
                        PARAM_FILE_NAME  3ob-parameter
                        DISPERSION_TYPE D3
                        DISPERSION_PARAMETER_FILE dftd3.dat
                        D3_SCALING  1.0 1.5 1.5
                        HB_SR_PARAM       4.85
                  &END PARAMETER
           &END DFTB
    &END QS   
    
    
    
    &SCF
      MAX_SCF 100
      EPS_SCF 1.0E-5
      SCF_GUESS RESTART
      &OT
        PRECONDITIONER FULL_SINGLE_INVERSE
        MINIMIZER DIIS
      &END OT
      &OUTER_SCF
        MAX_SCF 20
        EPS_SCF 1.0E-5
      &END

    &END SCF

  &END DFT





   
   &SUBSYS
     &CELL
       A     ${ABC}   0   0    
       B     0    ${ABC}  0
       C     0    0   ${ABC}
       PERIODIC  NONE
     &END CELL

     @INCLUDE colvar.inp

     &TOPOLOGY
       COORD_FILE_NAME ${sys}.xyz
       COORD_FILE_FORMAT  XYZ
       NUMBER_OF_ATOMS  ${natm}
     &END TOPOLOGY
   &END SUBSYS
 &END FORCE_EVAL

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