forked from lijiext/lammps
143 lines
5.0 KiB
Plaintext
143 lines
5.0 KiB
Plaintext
"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
|
|
|
|
next command :h3
|
|
|
|
[Syntax:]
|
|
|
|
next variables :pre
|
|
|
|
variables = one or more variable names :ul
|
|
|
|
[Examples:]
|
|
|
|
next x
|
|
next a t x myTemp :pre
|
|
|
|
[Description:]
|
|
|
|
This command is used with variables defined by the
|
|
"variable"_variable.html command. It assigns the next value to the
|
|
variable from the list of values defined for that variable by the
|
|
"variable"_variable.html command. Thus when that variable is
|
|
subsequently substituted for in an input script command, the new value
|
|
is used.
|
|
|
|
See the "variable"_variable.html command for info on how to define and
|
|
use different kinds of variables in LAMMPS input scripts. If a
|
|
variable name is a single lower-case character from "a" to "z", it can
|
|
be used in an input script command as $a or $z. If it is multiple
|
|
letters, it can be used as $\{myTemp\}.
|
|
|
|
If multiple variables are used as arguments to the {next} command,
|
|
then all must be of the same variable style: {index}, {loop}, {file},
|
|
{universe}, or {uloop}. An exception is that {universe}- and
|
|
{uloop}-style variables can be mixed in the same {next} command.
|
|
|
|
All the variables specified with the next command are incremented by
|
|
one value from their respective list of values. A {file}-style
|
|
variable reads the next line from its associated file. An
|
|
{atomfile}-style variable reads the next set of lines (one per atom)
|
|
from its associated file. {String-} or {atom}- or {equal}- or
|
|
{world}-style variables cannot be used with the the next command,
|
|
since they only store a single value.
|
|
|
|
When any of the variables in the next command has no more values, a
|
|
flag is set that causes the input script to skip the next
|
|
"jump"_jump.html command encountered. This enables a loop containing
|
|
a next command to exit. As explained in the "variable"_variable.html
|
|
command, the variable that has exhausted its values is also deleted.
|
|
This allows it to be used and re-defined later in the input script.
|
|
{File}-style and {atomfile}-style variables are exhausted when the
|
|
end-of-file is reached.
|
|
|
|
When the next command is used with {index}- or {loop}-style variables,
|
|
the next value is assigned to the variable for all processors. When
|
|
the next command is used with {file}-style variables, the next line is
|
|
read from its file and the string assigned to the variable. When the
|
|
next command is used with {atomfile}-style variables, the next set of
|
|
per-atom values is read from its file and assigned to the variable.
|
|
|
|
When the next command is used with {universe}- or {uloop}-style
|
|
variables, all {universe}- or {uloop}-style variables must be listed
|
|
in the next command. This is because of the manner in which the
|
|
incrementing is done, using a single lock file for all variables. The
|
|
next value (for each variable) is assigned to whichever processor
|
|
partition executes the command first. All processors in the partition
|
|
are assigned the same value(s). Running LAMMPS on multiple partitions
|
|
of processors via the "-partition" command-line switch is described in
|
|
"this section"_Section_start.html#start_7 of the manual. {Universe}-
|
|
and {uloop}-style variables are incremented using the files
|
|
"tmp.lammps.variable" and "tmp.lammps.variable.lock" which you will
|
|
see in your directory during and after such a LAMMPS run.
|
|
|
|
Here is an example of running a series of simulations using the next
|
|
command with an {index}-style variable. If this input script is named
|
|
in.polymer, 8 simulations would be run using data files from
|
|
directories run1 thru run8.
|
|
|
|
variable d index run1 run2 run3 run4 run5 run6 run7 run8
|
|
shell cd $d
|
|
read_data data.polymer
|
|
run 10000
|
|
shell cd ..
|
|
clear
|
|
next d
|
|
jump in.polymer :pre
|
|
|
|
If the variable "d" were of style {universe}, and the same in.polymer
|
|
input script were run on 3 partitions of processors, then the first 3
|
|
simulations would begin, one on each set of processors. Whichever
|
|
partition finished first, it would assign variable "d" the 4th value
|
|
and run another simulation, and so forth until all 8 simulations were
|
|
finished.
|
|
|
|
Jump and next commands can also be nested to enable multi-level loops.
|
|
For example, this script will run 15 simulations in a double loop.
|
|
|
|
variable i loop 3
|
|
variable j loop 5
|
|
clear
|
|
...
|
|
read_data data.polymer.$i$j
|
|
print Running simulation $i.$j
|
|
run 10000
|
|
next j
|
|
jump in.script
|
|
next i
|
|
jump in.script :pre
|
|
|
|
Here is an example of a double loop which uses the "if"_if.html and
|
|
"jump"_jump.html commands to break out of the inner loop when a
|
|
condition is met, then continues iterating thru the outer loop.
|
|
|
|
label loopa
|
|
variable a loop 5
|
|
label loopb
|
|
variable b loop 5
|
|
print "A,B = $a,$b"
|
|
run 10000
|
|
if $b > 2 then "jump in.script break"
|
|
next b
|
|
jump in.script loopb
|
|
label break
|
|
variable b delete :pre
|
|
next a
|
|
jump in.script loopa :pre
|
|
|
|
[Restrictions:]
|
|
|
|
As described above.
|
|
|
|
[Related commands:]
|
|
|
|
"jump"_jump.html, "include"_include.html, "shell"_shell.html,
|
|
"variable"_variable.html,
|
|
|
|
[Default:] none
|