Parameters

Following is a complete list of all potfit parameters, together with a short description of their meaning, and indications when they are needed. Floating point numbers should be given in decimal notation. Vectors are given as a list of components, separated by spaces or tabs (all on one line).

An asterisk (*) marks required parameters.

parameter name	parameter type	default value
short explanation

main parameters

ntypes*	integer	(none)
number of atom types (types vary in [0,..,ntypes-1])

file names

config*	string	(none)
file with atomic configurations in force format, see Configurations

startpot*	string	(none)
file name containing the starting potential, see Potential files

tempfile*	string	(none)
file name for temporary (intermediate) potentials, see tempfile

endpot	string	$startpot_end
file name for final potential, see Potential files

imdpot	string	(none)
file name prefix for imd potentials, see IMD

plotfile	string	(none)
file name for plotting potential, see plotfile

flagfile	string	(none)
file, whose presence terminates the current fit, see Flagfile

general options

write_pair	boolean	0
write radial pair distribution, see Pair distribution

write_lammps	boolean	0
write potential in LAMMPS format, see LAMMPS

cell_scale	float	1.0
rescale all cells, see cell_scale

Minimization options

opt	boolean	0
whether or not to perform an optimization

eng_weight*	float	(none)
weight of energy in minimization, see Algorithms

stress_weight	float	(none)
(* if compiled with `stress`) weight of stress in minimiziation, see Algorithms

anneal_temp	float	1.0
starting temperature for simulated annealing, set to 0 to skip simulated annealing, see Simulated Annealing

evo_threshold	float	1.0
stop the evolutionary algorithm if the difference in the population is smaller than this, set to zero to skip evo, see Differential Evolution

d_eps	float	0.0
error margin for powell minimization - if the improvement is smaller, the optimization is stopped, see lsq

seed	integer	4
seed for random number generator

apot_punish	float	0.0
scaling factor for apot punishments, this does not affect out-of-bounds punishment, see Analytic potentials/Punishments

options only for tabulated potentials

plotpointfile*	string	(none)
file name for plotting the sampling points, see plotpointfile

distfile	string	(none)
file name for distribution file (* with compile option 'dist'), see bindistfile

maxchfile	string	(none)
file with maximal permissible changes for each parameter, see Maxchfile

options only for analytic potentials

plotmin	float	0.0
starting point for plotting potentials, see plotfile

enable_cp	boolean	0
whether or not to include chemical potentials, see pair_potentials

options for output

imdpotsteps	integer	500
number of sampling points in each function in imd potential files, see IMD

output_prefix	string	(none)
prefix for various output files, see Output

extend	float	2.0
how many steps should the imd potentials be extrapolated, see IMD

lammpspotsteps	integer	500
number of sampling points in each funcation in LAMMPS potential files, see LAMMPS

parameter for option coulomb

dp_cut	float	10
cutoff-radius for electrostatic interactions, doesn't depend on other pair-function-radii.

parameters for option dipole

dp_tol	float	1.e-7
dipole iteration precision.

dp_mix	float	0.2
mixing parameter for dipole convergence during iteration.

parameters for OpenKIM potentials

The options for OpenKIM potentials are described in more detail on the OpenKIM page.

kim_model_name	string	(none)
KIM model indentifier

kim_model_params	string	(none)
Special parameter option, see OpenKIM page for details

kim_model_output_directory	string	(none)
Output directory for the optimized KIM model

kim_model_output_name	string	(none)
Name for the optimized KIM model