%METAVAR%TEMP_TOL Vs. %METAVAR%WALL

[Francesco]

Hi,

trying to increase my confidence with cp2k & metadynamics by
reproducing the SN2 reaction
of Ensing et al.  At the moment I'm using an extended lagrangian with
walls to constrain
the colvar, no hills yet. I've had some problems to
add the walls on the colvar, since I found difficult to turn them on.

In principle, there is a wall_minus at -4 and a wall_plus at +4,
colvar is around -2 at
the beginning of the simulation. To test that the walls were active, I
did a very simple
test.  I put wall_minus at +4 and wall_plus at -4.
This way, at the first MD step I should find crazy potential energy.

However, if I set any TEMP_TOL (from 0.0 to 1.E10) for the METAVAR
%ROOT%MOTION%FREE_ENERGY%METADYN%TEMP_TOL
nothing happens, the potential energy at the first MD step is the
total scf energy.

As I simply remove the TEMP_TOL for the METAVAR from the input, the
potential energy at
the first MD step, as expected, goes crazy because of the walls.

In short, it seems to me that the walls are active if TEMP_TOL on the
METAVAR is not
included in the input. Is it that normal ? Am I missing something of
the story ?

Here is the input for a fast (less then 5 mins on a Xeon quadcore)
test.
Thanks,
francesco



&MOTION
   &MD
     COMVEL_TOL 1.0E-08
     ANGVEL_ZERO T
     ENSEMBLE NVT
     TEMPERATURE 300.0
     STEPS 10
     TIMESTEP 0.5
     &THERMOSTAT
        TYPE NOSE
        REGION GLOBAL
        &NOSE
        &END NOSE
     &END THERMOSTAT
   &END MD
   &FREE_ENERGY
     METHOD METADYN
     &METADYN
       DO_HILLS F
       LAGRANGE T
       TEMPERATURE 300.0
       TEMP_TOL 80.0
       WW 0.0005
       &METAVAR
         MASS 10.0
         SCALE 0.15
         LAMBDA 0.5
         COLVAR 1
         &WALL
           TYPE QUADRATIC
           POSITION 4.0
           &QUADRATIC
             K 100.0
             DIRECTION WALL_MINUS
           &END QUADRATIC
         &END WALL
         &WALL
           TYPE QUADRATIC
           POSITION -4.0
           &QUADRATIC
             K 100.0
             DIRECTION WALL_PLUS
           &END QUADRATIC
         &END WALL
       &END METAVAR
       &PRINT
         &COLVAR
           FILENAME =colvar
         &END COLVAR
       &END PRINT
     &END METADYN
   &END FREE_ENERGY
   &PRINT
     &TRAJECTORY
       &EACH
         MD 2
       &END EACH
     &END TRAJECTORY
     &VELOCITIES
       &EACH
         MD 2
       &END EACH
     &END VELOCITIES
     &RESTART
       &EACH
         MD 10
       &END EACH
     &END RESTART
   &END PRINT
   &GEO_OPT
   &END GEO_OPT
&END MOTION
&FORCE_EVAL
   METHOD Quickstep
   &DFT
      &POISSON
          POISSON_SOLVER WAVELET
          PERIODIC NONE
      &END POISSON
      BASIS_SET_FILE_NAME BASIS_AU
      POTENTIAL_FILE_NAME POT_AU
      CHARGE -1
     &MGRID
       CUTOFF 280
     &END MGRID
     &QS
       EXTRAPOLATION ASPC
       EXTRAPOLATION_ORDER 3
     &END QS
     &SCF
       EPS_SCF 1.0E-6
       SCF_GUESS ATOMIC
       &PRINT
         &RESTART OFF
         &END
       &END PRINT
       &OT
         MINIMIZER DIIS
         N_DIIS 7
         PRECONDITIONER FULL_SINGLE_INVERSE
       &END OT
       &OUTER_SCF
         EPS_SCF 1.0E-4
         MAX_SCF 4
       &END OUTER_SCF
     &END SCF
     &XC
       &XC_FUNCTIONAL BLYP
       &END XC_FUNCTIONAL
     &END XC
   &END DFT
   &SUBSYS
     &CELL
       ABC 12.0 12.0 12.0
       UNIT ANGSTROM
       PERIODIC NONE
     &END CELL
     &COORD
  C      6.21755040790000        6.27945039380000
5.87094203540000
  Cl     8.06896049700000        6.19655506190000
6.18039982360000
  Cl     3.14468329460000        5.68026996200000
5.90402508870000
  H      5.81537329980000        6.79388677010000
6.75597666210000
  H      5.90571792570000        5.23287421340000
5.79791183930000
  H      6.05556449220000        6.86392371860000
4.95315969410000
     &END COORD
     &VELOCITY
  -2.214634000000000E-004 -2.388178000000000E-004
-4.611093000000000E-004
  -3.043920000000000E-005  6.815900000000000E-005
1.200276000000000E-004
   1.033677000000000E-004  4.250750000000000E-005
6.534730000000000E-005
  -3.199348000000000E-004 -1.111403800000000E-003
-3.637730000000000E-005
   3.678017000000000E-004  2.676782000000000E-004
-7.108579000000001E-004
   2.604120000000000E-005 -2.029183000000000E-004
-2.782362000000000E-004
     &END VELOCITY
     &KIND H
       BASIS_SET DZVP-GTH-BLYP
       POTENTIAL GTH-BLYP-q1
     &END KIND
     &KIND C
       BASIS_SET DZVP-GTH-BLYP
       POTENTIAL GTH-BLYP-q4
     &END KIND
     &KIND Cl
       BASIS_SET DZVP-GTH-BLYP
       POTENTIAL GTH-BLYP-q7
     &END KIND
     &COLVAR
       &DISTANCE_DIFFERENCE
          ATOMS 1 2 1 3
       &END DISTANCE_DIFFERENCE
     &END COLVAR
   &END SUBSYS
&END FORCE_EVAL
&GLOBAL
   RUN_TYPE MD
   PROJECT cp2k
   PRINT_LEVEL LOW
&END GLOBAL