use proper units (fmsec -> fs, psec -> ps and so on)

whatever :doc:`units <units>` style is being used, to write out

coordinates in nanometers and time in picoseconds.  I.e. for *real*

units, LAMMPS defines *sfactor* = 0.1 and *tfactor* = 0.001, since the

Angstroms and fmsec used by *real* units are 0.1 nm and 0.001 psec

Angstroms and fs used by *real* units are 0.1 nm and 0.001 ps

respectively.  If you are using a units system with distance and time

units far from nm and psec, you may wish to write XTC files with

units far from nm and ps, you may wish to write XTC files with

different units, since the compression algorithm used in XTC files is

most effective when the typical magnitude of position data is between

10.0 and 0.1.

engineering strain rate", where rate = V/L0 and L0 is the initial box

length.  The distance can be in lattice or box distance units.  See

the discussion of the units keyword below.  For example, if the

initial box length is 100 Angstroms, and V is 10 Angstroms/psec, then

after 10 psec, the box length will have doubled.  After 20 psec, it

initial box length is 100 Angstroms, and V is 10 Angstroms/ps, then

after 10 ps, the box length will have doubled.  After 20 ps, it

will have tripled.

The *erate* style changes a dimension of the box at a "constant

where dt is the elapsed time (in time units).  Thus if *erate* R is

specified as 0.1 and time units are picoseconds, this means the box

length will increase by 10% of its original length every picosecond.

I.e. strain after 1 psec = 0.1, strain after 2 psec = 0.2, etc.  R =

I.e. strain after 1 ps = 0.1, strain after 2 ps = 0.2, etc.  R =

-0.01 means the box length will shrink by 1% of its original length

every picosecond.  Note that for an "engineering" rate the change is

based on the original box length, so running with R = 1 for 10

where dt is the elapsed time (in time units).  Thus if *trate* R is

specified as ln(1.1) and time units are picoseconds, this means the

box length will increase by 10% of its current (not original) length

every picosecond.  I.e. strain after 1 psec = 0.1, strain after 2 psec

every picosecond.  I.e. strain after 1 ps = 0.1, strain after 2 ps

= 0.21, etc.  R = ln(2) or ln(3) means the box length will double or

triple every picosecond.  R = ln(0.99) means the box length will

shrink by 1% of its current length every picosecond.  Note that for a

initial box length perpendicular to the direction of shear.  The

distance can be in lattice or box distance units.  See the discussion

of the units keyword below.  For example, if the initial tilt factor

is 5 Angstroms, and the V is 10 Angstroms/psec, then after 1 psec, the

tilt factor will be 15 Angstroms.  After 2 psec, it will be 25

is 5 Angstroms, and the V is 10 Angstroms/ps, then after 1 ps, the

tilt factor will be 15 Angstroms.  After 2 ps, it will be 25

Angstroms.

The *erate* style changes a tilt factor at a "constant engineering

deformation), and dt is the elapsed time (in time units).  Thus if

*erate* R is specified as 0.1 and time units are picoseconds, this

means the shear strain will increase by 0.1 every picosecond.  I.e. if

the xy shear strain was initially 0.0, then strain after 1 psec = 0.1,

strain after 2 psec = 0.2, etc.  Thus the tilt factor would be 0.0 at

time 0, 0.1\*ybox at 1 psec, 0.2\*ybox at 2 psec, etc, where ybox is the

the xy shear strain was initially 0.0, then strain after 1 ps = 0.1,

strain after 2 ps = 0.2, etc.  Thus the tilt factor would be 0.0 at

time 0, 0.1\*ybox at 1 ps, 0.2\*ybox at 2 ps, etc, where ybox is the

original y box length.  R = 1 or 2 means the tilt factor will increase

by 1 or 2 every picosecond.  R = -0.01 means a decrease in shear

strain by 0.01 every picosecond.

time units).  Thus if *trate* R is specified as ln(1.1) and time units

are picoseconds, this means the shear strain or tilt factor will

increase by 10% every picosecond.  I.e. if the xy shear strain was

initially 0.1, then strain after 1 psec = 0.11, strain after 2 psec =

initially 0.1, then strain after 1 ps = 0.11, strain after 2 ps =

0.121, etc.  R = ln(2) or ln(3) means the tilt factor will double or

triple every picosecond.  R = ln(0.99) means the tilt factor will

shrink by 1% every picosecond.  Note that the change is continuous, so

If *eflux* is a numeric constant or equal-style variable which evaluates

to a scalar value, then *eflux* determines the change in aggregate energy

of the entire group of atoms per unit time, e.g. in eV/psec for

of the entire group of atoms per unit time, e.g. in eV/ps for

:doc:`metal units <units>`.  In this case it is an "extensive" quantity,

meaning its magnitude should be scaled with the number of atoms in the

group.  Note that since *eflux* also has per-time units (i.e. it is a

*damp_com* is the characteristic time for reaching thermal equilibrium

of the centers of mass.  For example, a value of 100.0 means to relax

the temperature of the centers of mass in a timespan of (roughly) 100

time units (tau or fmsec or psec - see the :doc:`units <units>`

time units (tau or fs or ps - see the :doc:`units <units>`

command).  *damp_drude* is the characteristic time for reaching

thermal equilibrium of the dipoles. It is typically a few timesteps.

to define the *linear* velocity and *wiggle* amplitude and *rotate*

origin.  This setting is ignored for the *variable* style.  A *box*

value selects standard units as defined by the :doc:`units <units>`

command, e.g. velocity in Angstroms/fmsec and amplitude and position

command, e.g. velocity in Angstroms/fs and amplitude and position

in Angstroms for units = real.  A *lattice* value means the velocity

units are in lattice spacings per time and the amplitude and position

are in lattice spacings.  The :doc:`lattice <lattice>` command must have