"gcmc"_fix_gcmc.html,

"gld"_fix_gld.html,

"gravity (o)"_fix_gravity.html,

"halt"_fix_halt.html,

"heat"_fix_heat.html,

"indent"_fix_indent.html,

"langevin (k)"_fix_langevin.html,

     id = sort per-atom lines by atom ID

     N = sort per-atom lines in ascending order by the Nth column

     -N = sort per-atom lines in descending order by the Nth column

  {thresh} args = attribute operation value

  {thresh} args = attribute operator value

    attribute = same attributes (x,fy,etotal,sxx,etc) used by dump custom style

    operation = "<" or "<=" or ">" or ">=" or "==" or "!=" or "|^"

    operator = "<" or "<=" or ">" or ">=" or "==" or "!=" or "|^"

    value = numeric value to compare to, or LAST

    these 3 args can be replaced by the word "none" to turn off thresholding

  {unwrap} arg = {yes} or {no} :pre

If an atom-style variable is used as the attribute, then it can

produce continuous numeric values or effective Boolean 0/1 values

which may be useful for the comparision operation.  Boolean values can

which may be useful for the comparision operator.  Boolean values can

be generated by variable formulas that use comparison or Boolean math

operators or special functions like gmask() and rmask() and grmask().

See the "variable"_variable.html command doc page for details.

E.g. due to reactions and subsequent charge equilibration in a

reactive force field.

The choice of operations are the usual comparison operators.  The XOR

The choice of operators are the usual comparison operators.  The XOR

operation (exclusive or) is also included as "|^".  In this context,

XOR means that if either the attribute or value is 0.0 and the other

is non-zero, then the result is "true" and the threshold criterion is

"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

fix halt command :h3

[Syntax:]

fix ID group-ID halt N attribute operator value keyword value ... :pre

ID, group-ID are documented in "fix"_fix.html command :ulb,l

halt = style name of this fix command :l

N = check halt condition every N steps :l

attribute = hstyle or v_name :l

  hstyle = {bondmax}

  v_name = name of "equal-style variable"_variable.html :pre

operator = "<" or "<=" or ">" or ">=" or "==" or "!=" or "|^" :l

value = numeric value to compare to :l

string = text string to print with optional variable names :l

zero or more keyword/value pairs may be appended :l

keyword = {error} :l

  {error} value = {hard} or {soft} or {continue} :pre

:ule

[Examples:]

fix 10 all halt 1 bondmax > 1.5

fix 10 all print 10 v_myCheck != 0 error soft :pre

[Description:]

Check a condition every N steps during a simulation run.  N must be >=

1.  If the condition is met, exit the run immediately.  In this

context a "run" can be dynamics or minimization iterations, as

specified by the "run"_run.html or "minimize"_minimize.html command.

The specified group-ID is ignored by this fix.

The specified {attribute} can be one of the {hstyle} options listed

above, or an "equal-style variable"_variable.html referenced as

{v_name}, where "name" is the name of a variable that has been defined

previously in the input script.

The only {hstyle} option currently implemented is {bondmax}.  This

will loop over all bonds in the system, compute their current

lengths, and set {attribute} to the longest bond distance.

Equal-style variables evaluate to a numeric value.  See the

"variable"_variable.html command for a description.  They calculate

formulas which can involve mathematical operations, atom properties,

group properties, thermodynamic properties, global values calculated

by a "compute"_compute.html or "fix"_fix.html, or references to other

"variables"_variable.html.  Thus they are a very general means of

computing some attribute of the current system.  For example, the

following "bondmax" variable will calculate the same quantity as the

hstyle = bondmax option.

compute         bdist all bond/local dist

compute         bmax all reduce max c_bdist

variable        bondmax equal c_bmax :pre

Thus these two versions of a fix halt command will do the same thing:

fix 10 all halt 1 bondmax > 1.5

fix 10 all halt 1 v_bondmax > 1.5 :pre

The version with "bondmax" will just run somewhat faster, due to less

overhead in computing bond lengths and not storing them in a separate

compute.

The optional {error} keyword determines how the current run is halted.

If its value is {hard}, then LAMMPS will stop with an error message.

If its value is {soft}, LAMMPS will exit the current run, but continue

to execute subsequent commands in the input script.  However,

additional "run"_run.html or "minimize"_minimize.html commands will be

skipped.  For example, this allows a script to output the current

state of the system, e.g. via a "write_dump"_write_dump.html or

"write_restart"_write_restart.html command.

If its value is {continue}, the behavior is the same as for {soft},

except subsequent subsequent "run"_run.html or

"minimize"_minimize.html commands are executed.  This allows your

script to remedy the condition that triggered the halt, if necessary.

Note that you may wish use the "unfix"_unfix.html command on the fix

halt ID, so that the same condition is not immediately triggered in a

subsequent run.

[Restart, fix_modify, output, run start/stop, minimize info:]

No information about this fix is written to "binary restart

files"_restart.html.  None of the "fix_modify"_fix_modify.html options

are relevant to this fix.  No global or per-atom quantities are stored

by this fix for access by various "output

commands"_Section_howto.html#howto_15.  No parameter of this fix can

be used with the {start/stop} keywords of the "run"_run.html command.

This fix is not invoked during "energy minimization"_minimize.html.

[Restrictions:] none

[Related commands:]

"variable"_variable.html

[Default:]

The option defaults are error = hard.

the number of outer iterations or timesteps exceeds {maxiter}

the number of total force evaluations exceeds {maxeval} :ul

NOTE: You can also use the "fix halt"_fix_halt.html command to specify

a general criterion for exiting a minimization, that is a calculation

performed on the state of the current system, as defined by an

"equal-style variable"_variable.html.

For the first criterion, the specified energy tolerance {etol} is

unitless; it is met when the energy change between successive

iterations divided by the energy magnitude is less than or equal to

run will print the full timing summary, but these operations will be

skipped for intermediate runs.

NOTE: You might hope to specify a command that exits the run by

NOTE: You might wish to specify a command that exits the run by

jumping out of the loop, e.g.

variable t equal temp

run 10000 every 100 "if '$t < 300.0' then 'jump SELF afterrun'" :pre

Unfortunately this will not currently work.  The run command simply

executes each command one at a time each time it pauses, then

continues the run.  You can replace the jump command with a simple

"quit"_quit.html command and cause LAMMPS to exit during the

middle of a run when the condition is met.

However, this will not work.  The run command simply executes each

command one at a time each time it pauses, then continues the run.

Instead, you should use the "fix halt"_fix_halt.html command, which

has additional options for how to exit the run.

[Restrictions:]

[Related commands:]

"minimize"_minimize.html, "run_style"_run_style.html,

"temper"_temper.html

"temper"_temper.html, "fix halt"_fix_halt.html

[Default:]