jianmu
/
lammps
forked from lijiext/lammps
1
0
Fork 0
Code Issues Pull Requests Packages Projects Releases Wiki Activity

git-svn-id: svn://svn.icms.temple.edu/lammps-ro/trunk@9296 f3b2605a-c512-4ea7-a41b-209d697bcdaa

This commit is contained in:
sjplimp 2013-01-18 16:58:14 +00:00
parent 7866cd6a29
commit 580cecfd09
4 changed files with 49 additions and 15 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

11
doc/fix_adapt.html
View File

@ -42,9 +42,8 @@
<PRE> <I>scale</I> value = <I>no</I> or <I>yes</I>
<I>no</I> = the variable value is the new setting
<I>yes</I> = the variable value multiplies the original setting
</PRE>
<PRE> <I>reset</I> value = <I>no</I> or <I>yes</I>
<I>yes</I> = the variable value multiplies the original setting
<I>reset</I> value = <I>no</I> or <I>yes</I>
<I>no</I> = values will remain altered at the end of a run
<I>yes</I> = reset altered values to their original values at the end of a run
</PRE>
@ -65,7 +64,11 @@ attributes which can be varied by this fix are discussed below. Many
other fixes can also be used to time-vary simulation parameters,
e.g. the "fix deform" command will change the simulation box
size/shape and the "fix move" command will change atom positions and
velocities in a prescribed manner.
velocities in a prescribed manner. Also note that many commands allow
variables as arguments for specific parameters, if described in that
manner on their doc pages. An equal-style variable can calculate a
time-dependent quantity, so this is another way to vary a simulation
parameter over time.
</P>
<P>If <I>N</I> is specified as 0, the specified attributes are only changed
once, before the simulation begins. This is all that is needed if the

8
doc/fix_adapt.txt
View File

@ -31,7 +31,7 @@ zero or more keyword/value pairs may be appended :l
keyword = {scale} or {reset} :l
{scale} value = {no} or {yes}
{no} = the variable value is the new setting
{yes} = the variable value multiplies the original setting :pre
{yes} = the variable value multiplies the original setting
{reset} value = {no} or {yes}
{no} = values will remain altered at the end of a run
{yes} = reset altered values to their original values at the end of a run :pre
@ -52,7 +52,11 @@ attributes which can be varied by this fix are discussed below. Many
other fixes can also be used to time-vary simulation parameters,
e.g. the "fix deform" command will change the simulation box
size/shape and the "fix move" command will change atom positions and
velocities in a prescribed manner.
velocities in a prescribed manner. Also note that many commands allow
variables as arguments for specific parameters, if described in that
manner on their doc pages. An equal-style variable can calculate a
time-dependent quantity, so this is another way to vary a simulation
parameter over time.
If {N} is specified as 0, the specified attributes are only changed
once, before the simulation begins. This is all that is needed if the

28
doc/fix_wall.html
View File

@ -29,14 +29,18 @@
<LI>face = <I>xlo</I> or <I>xhi</I> or <I>ylo</I> or <I>yhi</I> or <I>zlo</I> or <I>zhi</I>
<PRE> args = coord epsilon sigma cutoff
<LI> args = coord epsilon sigma cutoff
coord = position of wall = EDGE or constant or variable
EDGE = current lo or hi edge of simulation box
constant = number like 0.0 or -30.0 (distance units)
variable = <A HREF = "variable.html">equal-style variable</A> like v_x or v_wiggle
epsilon = strength factor for wall-particle interaction (energy or energy/distance^2 units)
sigma = size factor for wall-particle interaction (distance units)
cutoff = distance from wall at which wall-particle interaction is cut off (distance units)
epsilon can be a variable (see below)
<LI> sigma = size factor for wall-particle interaction (distance units)
sigma can be a variable (see below)
<PRE> cutoff = distance from wall at which wall-particle interaction is cut off (distance units)
</PRE>
<LI>zero or more keyword/value pairs may be appended
@ -47,9 +51,8 @@
<I>box</I> = the wall position is defined in simulation box units
<I>fld</I> value = <I>yes</I> or <I>no</I>
<I>yes</I> = invoke the wall constraint to be compatible with implicit FLD
<I>no</I> = invoke the wall constraint in the normal way
</PRE>
<PRE> <I>pbc</I> value = <I>yes</I> or <I>no</I>
<I>no</I> = invoke the wall constraint in the normal way
<I>pbc</I> value = <I>yes</I> or <I>no</I>
<I>yes</I> = allow periodic boundary in a wall dimension
<I>no</I> = require non-perioidic boundaries in any wall dimension
</PRE>
@ -144,6 +147,16 @@ constant K, and has units (energy/distance^2). The input parameter
spring is at the <I>cutoff</I>. This is a repulsive-only spring since the
interaction is truncated at the <I>cutoff</I>
</P>
<P>For any wall, the <I>epsilon</I> and/or <I>sigma</I> parameter can be specified
as an <A HREF = "variable.html">equal-style variable</A>, in which case it should be
specified as v_name, where name is the variable name. As with a
variable wall position, the variable is evaluated each timestep and
the result becomes the current epsilon or sigma of the wall.
Equal-style variables can specify formulas with various mathematical
functions, and include <A HREF = "thermo_style.html">thermo_style</A> command
keywords for the simulation box parameters and timestep and elapsed
time. Thus it is easy to specify a time-dependent wall interaction.
</P>
<P>IMPORTANT NOTE: For all of the styles, you must insure that r is
always > 0 for all particles in the group, or LAMMPS will generate an
error. This means you cannot start your simulation with particles at
@ -194,7 +207,8 @@ want.
<P>Here are examples of variable definitions that move the wall position
in a time-dependent fashion using equal-style
<A HREF = "variable.html">variables</A>.
<A HREF = "variable.html">variables</A>. The wall interaction parameters (epsilon,
sigma) could be varied with additional variable definitions.
</P>
<PRE>variable ramp equal ramp(0,10)
fix 1 all wall xlo v_ramp 1.0 1.0 2.5

17
doc/fix_wall.txt
View File

@ -25,7 +25,9 @@ face = {xlo} or {xhi} or {ylo} or {yhi} or {zlo} or {zhi} :l
constant = number like 0.0 or -30.0 (distance units)
variable = "equal-style variable"_variable.html like v_x or v_wiggle
epsilon = strength factor for wall-particle interaction (energy or energy/distance^2 units)
epsilon can be a variable (see below) :l
sigma = size factor for wall-particle interaction (distance units)
sigma can be a variable (see below) :l
cutoff = distance from wall at which wall-particle interaction is cut off (distance units) :pre
zero or more keyword/value pairs may be appended :l
keyword = {units} or {fld} :l
@ -34,7 +36,7 @@ keyword = {units} or {fld} :l
{box} = the wall position is defined in simulation box units
{fld} value = {yes} or {no}
{yes} = invoke the wall constraint to be compatible with implicit FLD
{no} = invoke the wall constraint in the normal way :pre
{no} = invoke the wall constraint in the normal way
{pbc} value = {yes} or {no}
{yes} = allow periodic boundary in a wall dimension
{no} = require non-perioidic boundaries in any wall dimension :pre
@ -129,6 +131,16 @@ constant K, and has units (energy/distance^2). The input parameter
spring is at the {cutoff}. This is a repulsive-only spring since the
interaction is truncated at the {cutoff}
For any wall, the {epsilon} and/or {sigma} parameter can be specified
as an "equal-style variable"_variable.html, in which case it should be
specified as v_name, where name is the variable name. As with a
variable wall position, the variable is evaluated each timestep and
the result becomes the current epsilon or sigma of the wall.
Equal-style variables can specify formulas with various mathematical
functions, and include "thermo_style"_thermo_style.html command
keywords for the simulation box parameters and timestep and elapsed
time. Thus it is easy to specify a time-dependent wall interaction.
IMPORTANT NOTE: For all of the styles, you must insure that r is
always > 0 for all particles in the group, or LAMMPS will generate an
error. This means you cannot start your simulation with particles at
@ -179,7 +191,8 @@ want.
Here are examples of variable definitions that move the wall position
in a time-dependent fashion using equal-style
"variables"_variable.html.
"variables"_variable.html. The wall interaction parameters (epsilon,
sigma) could be varied with additional variable definitions.
variable ramp equal ramp(0,10)
fix 1 all wall xlo v_ramp 1.0 1.0 2.5 :pre