quench_steps
| Format: | quench_steps N |
| Description: | Determines maximum number of quench steps, if quench is requested. |
| Examples: | quench_steps 100 |
| Default: | 1000 |
cell_control
| Format: | cell_control C(*) |
| Description: | Determines the changes of the primitive cell during energy minimization. Possible values are: fixed_cell: constant volume and shape free_cell: change both volume and shape orthorhombic_cell: change both volume and shape, but hold orthorhombic cell shape hydrostatic_pressure: change the volume, but keep the shape In the earlier version of PhonTS, ‘barostat’ keyword was used followed by the integer to control this. Keyword is still accepted, but integerhas to be replaced by the by one of the specifications above. |
| Examples: | cell_control free_cell |
| Default: | fixed_cell |
atom_min_step
| Format: | atom_min_step R |
| Description: | Specifies the scaling parameter for forces during energy optimization by the primitive steepest descent gradient algorithm. The size of the step can be adjusted through the minimization process if Change_q_step keyword is specified, which provides a maximum values for the atomic and cell steps. In the earlier versions of PhonTS, ‘atom_quench’ keyword was used, which is still accepted for backwards compartibility. |
| Examples: | atom_min_step 0.0001 |
| Default: | 0.000001 |
cell_min_step
| Format: | cell_min_step R |
| Description: | Same as ‘atom_min_step’, but for the optimization of cell parameters, if appropriate settings for ‘cell_control’ is specified. In the earlier versions of PhonTS, ‘atom_quench’ keyword was used, which is still accepted for backwards compartibility. |
| Examples: | cell_min_step 0.01 |
| Default: | 0.1 |
max_force
| Format: | max_force R |
| Description: | Stopping criteria for the energy minimization: all forces in the system are less than specified value. For the shell model recommended value is 1e-6, slightly greater than default |
| Examples: | max_force 10-6 |
| Default: | 10-8 |
quench_only
| Format: | quench_only L |
| Description: | Only performes energy minimization and quit. Useful for the verufucation purposes, and only works with the classical potentials implemented within PhonTS (with the exception of Stillinger-Weber, where first derivatives are not available) |
| Examples: | quench_only T |
| Default: | False |
dump
| Format: | dump N |
| Description: | Controls how often (every Nth step) quench routine reports progress. |
| Examples: | dump 100 |
| Default: | 1 |
change_q_step
| Format: | change_q_step R1 R2 |
| Description: | Specifies that quench step can change throughout optimization.Adjustment of the stepsize is done on the basis of simple parabolic extrapolation of two consequent optimization steps. In order to avoid very ambitious large step, upper limits for the magnitude of the atomic (R1) and cell (R2) steps have to be provided here. |
| Examples: | change_q_step 0.00001 0.005 |
| Default: | Not set |