This page gives hints on how to perform a geometry optimization with the ABINIT package.
Different algorithms (Broyden; modified Broyden; Verlet with sudden stop of atoms, FIRE) allows to find the equilibrium configuration of the nuclei, for which the forces vanish, see ionmov. The cell parameters can also be optimized concurently with the atomic positions optcell, possibly with a state of given stress as a target, strtarget.
Specified lattice parameters, or angles, or atomic positions, can be kept fixed if needed, see topic_GeoConstraints.
A genetic algorithm has been coded, for global optimisation. See ga_rules. Not in production yet.
The results of the structural relaxation are saved in the HIST.nc file. This file can be used to restart the calculation or to analyze the results at the end of calculation. For further details about the AbiPy API please consult the HistFile notebook .
Related Input Variables¶
- dilatmx lattice DILATation: MaXimal value
- ntime Number of TIME steps
- strfact STRess FACTor
- tolmxde TOLerance on the MaXimal Difference in Energy
- tolmxf TOLerance on the MaXimal Force
- iprcfc Integer for PReConditioner of Force Constants
- restartxf RESTART from (X,F) history
- strprecon STRess PRECONditioner
- strtarget STRess TARGET
- chkdilatmx CHecK DILATMX
- fxcartfactor Forces to (X) CARTesian coordinates FACTOR
- ga_algor Genetic Algorithm - ALGOrithm selection
- ga_fitness Genetic Algorithm FITNESS function selection
- ga_n_rules Genetic Algorithm Number of RULES
- ga_opt_percent Genetic Algorithm OPTimal PERCENT
- ga_rules Genetic Algorithm RULES
- goprecon Geometry Optimization PRECONditioner equations
- goprecprm Geometry Optimization PREconditioner PaRaMeters equations
- random_atpos RANDOM ATomic POSitions
Selected Input Files¶