# Stress Tensor forcing SCF Wavefunction Optimization

Rafael Soler-Crespo rasole... at gmail.com
Thu May 1 17:06:56 UTC 2014

```Hi all,

Just to clarify, what I refer is that the box updating the progress of the
geometry optimization:

--------  Informations at step =     1 ------------

Optimization Method        =                 BFGS
Total Energy               =      -495.6366242369
Real energy change         =        -2.2642515093
Predicted change in energy =        -2.7904990758
Scaling factor             =         0.5267466124
Step size                  =         0.4724315332
Decrease in energy         =                  YES
Used time                  =               95.726

Convergence check :
Max. step size             =         0.4724315332
Conv. limit for step size  =         0.0030000000
Convergence in step size   =                   NO
RMS step size              =         0.1432565779
Conv. limit for RMS step   =         0.0015000000
Convergence in RMS step    =                   NO
Conv. limit for gradients  =         0.0004500000
Conv. limit for RMS grad.  =         0.0003000000
---------------------------------------------------

Is gone, and the program just keeps looping over the SCF wavefunctions. It
could possibly be that the optimization algorithm changed (since I haven't
specified it). Also, I can't find the stresses printed in the log file (or
in a separate file if I specify it).

I checked if the algorithm had changed (say, from BFGS to CG) but it
didn't. It's still BFGS for all my trial runs.

Thanks,
Rafael

On Thursday, May 1, 2014 11:54:13 AM UTC-5, Rafael Soler-Crespo wrote:
>
> Hi all,
>
> I'm using the code to print the stresses on a system that I am running.
> Currently, the system has the input file I show below. For some reason, if
> I take off the evaluation of the stress tensor, it proceeds fine and
> carries out one optimization step after the initial SCF Wavefunction
> optimization. However, when I desire to evaluate the stress tensor, it just
> keeps doing SCF Wavefunction optimizations over and over. Could someone
> shed some insight into this?
>
> Could it have to do with me using a numerical form of the stress tensor?
>
> Thanks,
> Rafael
> =================
> INPUT CODE
>
> &FORCE_EVAL
> STRESS_TENSOR NUMERICAL
>  &DFT
>   &QS
>    METHOD DFTB
>    &DFTB
>     SELF_CONSISTENT T
>     DO_EWALD     F
>     DISPERSION      F
>     &PARAMETER
>      PARAM_FILE_PATH /home/ras536/dftb_parameter_sets/cp2k/scc/
>      PARAM_FILE_NAME parameter_table
>      UFF_FORCE_FIELD uff_table
>     &END PARAMETER
>    &END DFTB
>   &END QS
>   &SCF
>    SCF_GUESS ATOMIC
>    MAX_SCF   200
>    &OT ON
>     LINESEARCH 3PNT
>     PRECONDITIONER FULL_SINGLE
>    &END OT
>   &END SCF
>  &END DFT
>  &SUBSYS
>   &CELL
> # Change with the system coordinates
>    ABC      21.50 22.14 100
>    PERIODIC XYZ
> # End of changes
>   &END CELL
>   &COORD
> # Paste here system coordinates
> # End of system coordinates
>   &END COORD
>  &END SUBSYS
>  &PRINT
>   &STRESS_TENSOR HIGH
>    FILENAME system_stress.log
>     &EACH
>      GEO_OPT 1
>     &END EACH
>   &END STRESS_TENSOR
>  &END PRINT
> &END FORCE_EVAL
>
>
> &GLOBAL
>   PROJECT     geo_opt_syst
>   RUN_TYPE    GEO_OPT
>   PRINT_LEVEL LOW
> &END GLOBAL
>
>
> &MOTION
>  &GEO_OPT
>   MAX_ITER 1000
>  &END GEO_OPT
> # Uncomment to allow fixed atoms
>  &CONSTRAINT
>   &FIXED_ATOMS
>    COMPONENTS_TO_FIX X
>    LIST 91 100 101 110 111 120 121 130 131 140 141 150 151 160 161 170
> 171 180
>   &END FIXED_ATOMS
>   &FIXED_ATOMS
>    COMPONENTS_TO_FIX Y
>    LIST 1 2 3 4 5 6 7 8 9 10 171 172 173 174 175 176 177 178 179 180
>   &END FIXED_ATOMS
>  &END CONSTRAINT
> # End of uncomment
> &END MOTION
>
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