forked from lijiext/lammps
68 lines
2.2 KiB
Plaintext
68 lines
2.2 KiB
Plaintext
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"LAMMPS WWW Site"_lws - "LAMMPS Documentation"_ld - "LAMMPS Commands"_lc :c
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:link(lws,http://lammps.sandia.gov)
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:link(ld,Manual.html)
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:link(lc,Section_commands.html#comm)
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:line
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min_modify command :h3
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[Syntax:]
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min_modify keyword values ... :pre
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one or more keyword/value pairs may be listed :ulb,l
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keyword = {linestyle} or {dmin} or {dmax} or {lineiter}
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{linestyle} value = {secant} or {scan}
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{dmin} value = min
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min = minimum distance for line search to move (distance units)
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{dmax} value = max
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max = maximum distance for line search to move (distance units)
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{lineiter} value = N
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N = max number of iterations in a line search :pre
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:ule
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[Examples:]
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min_modify linestyle scan dmin 0.001 dmax 0.2
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min_modify lineiter 5 :pre
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[Description:]
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This command sets parameters that affect the minimization algorithms.
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The various settings may effect the convergence rate and overall
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number of force evaulations required by a minimization, so users can
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experiment with these parameters to tune their minimizations.
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The {linestyle} sets the algorithm used for 1d line searches at each
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outer iteration of the minimizer. The {secant} style uses two
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successive force/energy evaluations to create a parabola and pick its
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minimum as an estimate of the next iteration's 1d minimum. The {scan}
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style starts its 1d search at {dmin} and doubles the distance along
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the line at which the energy is computed until the minimum is passed.
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It continues only as far as {dmax}. Normally, the {secant} method
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should find more accurate 1d minimums in less iterations, but the
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{scan} method can be more robust.
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The {dmin} and {dmax} settings are both used by the {scan} line search
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as described above. For the {secant} line search, only the {dmin}
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value is used to pick an initial point to begin the secant
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approximation.
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The {lineiter} setting is used by the {secant} algorithm to limit its
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iterations. The smaller the setting, the more inaccurate the line
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search becomes. Nonlinear conjugate gradient is not thought to
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require high-accuracy line searches in order to converge efficiently.
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[Restrictions:] none
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[Related commands:]
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"min_style"_min_style.html, "minimize"_minimize.html
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[Default:]
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The option defaults are linestyle = secant, dmin = 1.0e-5, dmax = 0.1,
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and lineiter = 10.
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