Miscellaneous:
-clear, echo, include, -jump, label, log, -next, print, shell, -variable +
clear, echo, if, +include, jump, label, +log, next, print, +shell, variable
Syntax: +
+if value1 operator value2 then command1 else command2 ++
Examples: +
+if $steps > 1000 then exit +if $x <= $y then "print X is smaller = $x" else "print Y is smaller = $y" +if $eng > 0.0 then "timestep 0.005" +if $eng > $eng_previous then "jump file1" else "jump file2" ++
Description: +
+This command provides an in-then-else test capability within an input +script. Two values are numerically compared to each other and the +result is TRUE or FALSE. Note that as in the examples above, either +of the values can be variables, as defined by the +variable command, so that when they are evaluated when +substituted for in the if command, a user-defined computation will be +performed which can depend on the current state of the simulation. +
+If the result of the if test is TRUE, then command1 is executed. This +can be any valid LAMMPS input script command. If the command is more +than 1 word, it should be enclosed in double quotes, so that it will +be treated as a single argument, as in the examples above. +
+The if command can contain an optional "else" clause. If it does and +the result of the if test is FALSE, then command2 is executed. +
+Note that if either command1 or command2 is a bogus LAMMPS command, +such as "exit" in the first example, then executing the command will +cause LAMMPS to halt. +
+Restrictions: none +
+Related commands: +
+variable +
+Default: none +
+ diff --git a/doc/if.txt b/doc/if.txt new file mode 100644 index 0000000000..e145463511 --- /dev/null +++ b/doc/if.txt @@ -0,0 +1,58 @@ +"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 + +if command :h3 + +[Syntax:] + +if value1 operator value2 then command1 else command2 :pre + +value1 = 1st value +operator = "==" or "!=" or "<" or "<=" or ">" or ">=" +value2 = 2nd value +then = required word +command1 = command to execute if condition is met +else = required word (optional argument) +command2 = command to execute if condition is not met (optional argument) :ul + +[Examples:] + +if ${steps} > 1000 then exit +if $x <= $y then "print X is smaller = $x" else "print Y is smaller = $y" +if ${eng} > 0.0 then "timestep 0.005" +if ${eng} > ${eng_previous} then "jump file1" else "jump file2" :pre + +[Description:] + +This command provides an in-then-else test capability within an input +script. Two values are numerically compared to each other and the +result is TRUE or FALSE. Note that as in the examples above, either +of the values can be variables, as defined by the +"variable"_variable.html command, so that when they are evaluated when +substituted for in the if command, a user-defined computation will be +performed which can depend on the current state of the simulation. + +If the result of the if test is TRUE, then command1 is executed. This +can be any valid LAMMPS input script command. If the command is more +than 1 word, it should be enclosed in double quotes, so that it will +be treated as a single argument, as in the examples above. + +The if command can contain an optional "else" clause. If it does and +the result of the if test is FALSE, then command2 is executed. + +Note that if either command1 or command2 is a bogus LAMMPS command, +such as "exit" in the first example, then executing the command will +cause LAMMPS to halt. + +[Restrictions:] none + +[Related commands:] + +"variable"_variable.html + +[Default:] none diff --git a/doc/run.html b/doc/run.html index 36faefedc4..e3147f330f 100644 --- a/doc/run.html +++ b/doc/run.html @@ -127,7 +127,7 @@ about how to couple LAMMPS to other codes. each M-length run, the command is invoked. If the command is specified as NULL, no command is invoked. Thus these lines: -variable q equal x100 +variable q equal x[100] run 6000 every 2000 "print Coord = $q"are the equivalent of: diff --git a/doc/run.txt b/doc/run.txt index 680526e996..b186b36c69 100644 --- a/doc/run.txt +++ b/doc/run.txt @@ -120,7 +120,7 @@ N total steps are simulated, in shorter runs of M steps each. After each M-length run, the command is invoked. If the command is specified as NULL, no command is invoked. Thus these lines: -variable q equal x[100] +variable q equal x\[100\] run 6000 every 2000 "print Coord = $q" :pre are the equivalent of: