Optimizer

The eon client provides three optimizers quick-min, conjugate gradients, and L-BFGS.

[Optimizer] parameters

opt_method: The optimization method to use.

default: cg

options:

box: Optimizes the atom positions and box using quickmin

cg: Conjugate gradient

qm: Quickmin

lbfgs: Limited Memory Broyden-Fletcher-Goldfarb-Shanno QuasiNewton optimizer

fire: Fast inertial relaxation engine

convergence_metric: The metric to use to determine when an optimization is complete.

default: norm

options:

norm: The norm of the entire force vector

max_atom: The maximum force on any non-frozen atom

max_component: The maximum force on any non-frozen degree of freedom

converged_force: When the convergence_metric is smaller than this value (eV/A), the structure is considered minimized.

default: 0.01

max_move: Maximum distance that an atom may be moved in a single optimization step (Angstoms).

default: 0.2

time_step: The dynamical timestep for the quickmin algorithm (fs).

default: 1.0

max_iterations: The maximum number of optimization iterations that the will be performed.

default: 1000

L-BFGS

The L-BFGS implementation in Eon resets its memory if a move larger than the max_move is attemped or if the angle between the force and the L-BFGS direction is larger than 90 degrees.

lbfgs_memory: The maximum number of previous gradients and positions that are kept in memory for the L-BFGS algorithm.

default: 20

lbfgs_inverse_curvature: The initial guess for inverse curvature at each step, which is used to construct the inverse Hessian matrix. This setting is only used when lbfgs_auto_scale is False.

default: 0.01

lbfgs_auto_scale: The initial guess for the inverse hessian at each step is constructed by estimating the curvature along the previous step direction. At the first step a forward finite difference calculation along the force is used to estimate the curvature.

default: True