"LAMMPS WWW Site"_lws - "LAMMPS Documentation"_ld - "LAMMPS Commands"_lc :c

:link(lws,http://lammps.sandia.gov)
:link(ld,Manual.html)
:link(lc,Section_commands.html#comm)

:line

min_modify command :h3

[Syntax:]

min_modify keyword values ... :pre

one or more keyword/value pairs may be listed :ulb,l
keyword = {linestyle} or {dmin} or {dmax} or {lineiter}
  {linestyle} value = {secant} or {scan}
  {dmin} value = min
    min = minimum distance for line search to move (distance units)
  {dmax} value = max
    max = maximum distance for line search to move (distance units)
  {lineiter} value = N
    N = max number of iterations in a line search :pre
:ule

[Examples:]

min_modify linestyle scan dmin 0.001 dmax 0.2
min_modify lineiter 5 :pre

[Description:]

This command sets parameters that affect the minimization algorithms.
The various settings may effect the convergence rate and overall
number of force evaulations required by a minimization, so users can
experiment with these parameters to tune their minimizations.

The {linestyle} sets the algorithm used for 1d line searches at each
outer iteration of the minimizer.  The {secant} style uses two
successive force/energy evaluations to create a parabola and pick its
minimum as an estimate of the next iteration's 1d minimum.  The {scan}
style starts its 1d search at {dmin} and doubles the distance along
the line at which the energy is computed until the minimum is passed.
It continues only as far as {dmax}.  Normally, the {secant} method
should find more accurate 1d minimums in less iterations, but the
{scan} method can be more robust.

The {dmin} and {dmax} settings are both used by the {scan} line search
as described above.  For the {secant} line search, only the {dmin}
value is used to pick an initial point to begin the secant
approximation.

The {lineiter} setting is used by the {secant} algorithm to limit its
iterations.  The smaller the setting, the more inaccurate the line
search becomes.  Nonlinear conjugate gradient is not thought to
require high-accuracy line searches in order to converge efficiently.

[Restrictions:] none

[Related commands:]

"min_style"_min_style.html, "minimize"_minimize.html

[Default:]

The option defaults are linestyle = secant, dmin = 1.0e-5, dmax = 0.1,
and lineiter = 10.
