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303 lines
14 KiB
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<CENTER><A HREF = "http://lammps.sandia.gov">LAMMPS WWW Site</A> - <A HREF = "Manual.html">LAMMPS Documentation</A> - <A HREF = "Section_commands.html#comm">LAMMPS Commands</A>
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<H3>thermo_style command
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</H3>
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<P><B>Syntax:</B>
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</P>
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<PRE>thermo_style style args
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</PRE>
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<UL><LI>style = <I>one</I> or <I>multi</I> or <I>granular</I> or <I>custom</I>
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<LI>args = list of arguments for a particular style
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<PRE> <I>one</I> args = none
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<I>multi</I> args = none
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<I>granular</I> args = none
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<I>custom</I> args = list of attributes
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possible attributes = step, atoms, cpu, temp, press,
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pe, ke, etotal, enthalpy,
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evdwl, ecoul, epair, ebond, eangle, edihed, eimp,
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emol, elong, etail,
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vol, lx, ly, lz, xlo, xhi, ylo, yhi, zlo, zhi,
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pxx, pyy, pzz, pxy, pxz, pyz
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drot, grot,
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c_ID, c_ID[n], f_ID, f_ID[n], v_name
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step = timestep
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atoms = # of atoms
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cpu = elapsed CPU time
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temp = temperature
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press = pressure
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pe = total potential energy
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ke = kinetic energy
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etotal = total energy (pe + ke)
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enthalpy = enthalpy (pe + press*vol)
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evdwl = VanderWaal pairwise energy
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ecoul = Coulombic pairwise energy
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epair = pairwise energy (evdwl + ecoul + elong + etail)
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ebond = bond energy
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eangle = angle energy
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edihed = dihedral energy
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eimp = improper energy
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emol = molecular energy (ebond + eangle + edihed + eimp)
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elong = long-range kspace energy
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etail = VanderWaal energy long-range tail correction
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vol = volume
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lx,ly,lz = box lengths in x,y,z
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xlo,xhi,ylo,yhi,zlo,zhi = box boundaries
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pxx,pyy,pzz,pxy,pxz,pyz = 6 components of pressure tensor
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drot = rotational energy of dipolar atoms
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grot = rotational energy of granular atoms
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c_ID = scalar quantity calculated by a compute identified by its ID
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c_ID[N] = Nth vector quantity calculated by a compute identified by its ID
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f_ID = scalar quantity calculated by a fix identified by its ID
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f_ID[N] = Nth vector quantity calculated by a fix identified by its ID
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v_name = current value of a variable identified by the variable name
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</PRE>
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</UL>
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<P><B>Examples:</B>
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</P>
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<PRE>thermo_style multi
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thermo_style custom step temp pe etotal press vol
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thermo_style custom step temp etotal c_myTemp v_abc
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</PRE>
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<P><B>Description:</B>
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</P>
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<P>Set the style and content for printing thermodynamic data to the
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screen and log file.
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</P>
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<P>Style <I>one</I> prints a one-line summary of thermodynamic info that is
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the equivalent of "thermo_style custom step temp epair emol etotal
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press". The line contains only numeric values.
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</P>
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<P>Style <I>multi</I> prints a multiple-line listing of thermodynamic info
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that is the equivalent of "thermo_style custom etotal ke temp pe ebond
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eangle edihed eimp evdwl ecoul elong press". The listing contains
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numeric values and a string ID for each quantity.
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</P>
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<P>Style <I>granular</I> is used with <A HREF = "atom_style.html">atom style</A> granular
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and prints a one-line numeric summary that is the equivalent of
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"thermo_style custom step atoms ke grot".
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</P>
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<P>Style <I>custom</I> is the most general setting and allows you to specify
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which of the keywords listed above you want printed on each
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thermodynamic timestep. Note that the keywords c_ID, f_ID, v_name are
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references to <A HREF = "compute.html">computes</A>, <A HREF = "fix.html">fixes</A>, and
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<A HREF = "variable.html"">variables</A> that have been defined elsewhere in the
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input script or can even be new styles which users have added to
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LAMMPS (see the <A HREF = "Section_modify.html">Section_modify</A> section of the
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documentation). Thus the <I>custom</I> style provides a flexible means of
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outputting essentially any desired quantity as a simulation proceeds.
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</P>
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<P>All styles except <I>custom</I> have <I>vol</I> appended to their list of
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outputs if the simulation box volume changes during the simulation.
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</P>
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<P>The values printed by the various keywords are instantaneous values,
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calculated on the current timestep. Time-averaged quantities, which
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include values from previous timesteps, can be output by using the
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f_ID keyword and accessing a fix that does time-averaging such as the
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<A HREF = "fix_ave_time.html">fix ave/time</A> command.
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</P>
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<P>Options invoked by the <A HREF = "thermo_modify.html">thermo_modify</A> command can
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be used to set the one- or multi-line format of the print-out, the
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normalization of energy quantities (total or per-atom), and the
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numeric precision of each printed value.
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</P>
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<P>IMPORTANT NOTE: When you specify a "thermo_style<A HREF = "thermo_modify.html"> command, all
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thermodynamic settings are restored to their default values, including
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those previously set by a :thermo_modify</A> command.
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Thus if your input script specifies a thermo_style command, you should
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use the thermo_modify command after it.
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</P>
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<HR>
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<P>Several of the thermodynamic quantities require a temperature to be
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computed: "temp", "press", "ke", "etotal", "enthalpy", "pxx etc". By
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default this is done by using the "thermo_temp" compute which is
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created when LAMMPS starts up, as if this command had been issued:
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</P>
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<PRE>compute thermo_temp all temp
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</PRE>
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<P>See the <A HREF = "compute_temp.html">compute temp</A> command for details. Note
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that the ID of this compute is <I>thermo_temp</I> and the group is <I>all</I>.
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You can change the attributes of this temperature (e.g. its
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degrees-of-freedom) via the <A HREF = "compute_modify.html">compute_modify</A>
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command. Alternatively, you can directly assign a new compute (that
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calculates temperature) which you have defined, to be used for
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calculating any thermodynamic quantity that requires a temperature.
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This is done via the <A HREF = "thermo_modify.html">thermo_modify</A> command.
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</P>
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<P>Several of the thermodynamic quantities require a pressure to be
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computed: "press", "enthalpy", "pxx", etc. By default this is done by
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using the "thermo_pressure" compute which is created when LAMMPS
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starts up, as if this command had been issued:
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</P>
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<PRE>compute thermo_pressure all pressure thermo_temp
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</PRE>
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<P>See the <A HREF = "compute_pressure.html">compute pressure</A> command for details.
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Note that the ID of this compute is <I>thermo_pressure</I> and the group is
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<I>all</I>. You can change the attributes of this pressure via the
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<A HREF = "compute_modify.html">compute_modify</A> command. Alternatively, you can
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directly assign a new compute (that calculates pressure) which you
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have defined, to be used for calculating any thermodynamic quantity
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that requires a pressure. This is done via the
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<A HREF = "thermo_modify.html">thermo_modify</A> command.
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</P>
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<P>Several of the thermodynamic quantities require a potential energy to
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be computed: "pe", "etotal", "ebond", etc. This is done by using the
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"thermo_pe" compute which is created when LAMMPS starts up, as if this
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command had been issued:
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</P>
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<PRE>compute thermo_pe all pe
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</PRE>
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<P>See the <A HREF = "compute_pe.html">compute pe</A> command for details. Note that
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the ID of this compute is <I>thermo_pe</I> and the group is <I>all</I>. You can
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change the attributes of this potential energy via the
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<A HREF = "compute_modify.html">compute_modify</A> command.
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</P>
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<P>The <I>drot</I> keyword requires a rotational energy to be computed for
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point dipole particles. To do this, a compute of style
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"rotate/dipole" is created, as if this command had been issued:
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</P>
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<PRE>compute thermo_rotate_dipole all rotate/dipole
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</PRE>
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<P>See the <A HREF = "compute_rotate_dipole.html">compute rotate/dipole</A> command for
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details. Note that the ID of the new compute is
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<I>thermo_rotate_dipole</I> and the group is <I>all</I>. You can change the
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attributes of this computation via the
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<A HREF = "compute_modify.html">compute_modify</A> command. Alternatively, you can
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directly assign a new compute which you have defined, to be used for
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<I>drot</I>. This is done via the <A HREF = "thermo_modify.html">thermo_modify</A>
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command. For example, this could be useful if you wish to exclude
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certain particles from the compuation.
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</P>
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<P>The <I>grot</I> keyword requires a rotational energy to be computed for
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granular particles. To do this, a compute of style "rotate/gran" is
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created, as if this command had been issued:
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</P>
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<PRE>compute thermo_rotate_gran all rotate/gran
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</PRE>
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<P>See the <A HREF = "compute_rotate_gran.html">compute rotate/gran</A> command for
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details. Note that the ID of the new compute is <I>thermo_rotate_gran</I>
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and the group is <I>all</I>. You can change the attributes of this
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computation via the <A HREF = "compute_modify.html">compute_modify</A> command.
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Alternatively, you can directly assign a new compute which you have
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defined, to be used for <I>grot</I>. This is done via the
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<A HREF = "thermo_modify.html">thermo_modify</A> command. For example, this could
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be useful if you wish to exclude frozen particles from the compuation.
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</P>
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<HR>
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<P>The potential energy of the system <I>pe</I> will include contributions
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from fixes if the <A HREF = "fix_modify.html">fix_modify thermo</A> option is set
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for a fix that calculates such a contribution. For example, the <A HREF = "fix_wall_lj93">fix
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wall/lj93</A> fix calculates the energy of atoms
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interacting with the wall. See the doc pages for "individual fixes"
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to see which ones contribute.
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</P>
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<P>A long-range tail correction <I>etail</I> for the VanderWaal pairwise
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energy will be non-zero only if the <A HREF = "pair_modify.html">pair_modify
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tail</A> option is turned on. The <I>etail</I> contribution
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is included in <I>evdwl</I>, <I>pe</I>, and <I>etotal</I>, and the corresponding tail
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correction to the pressure is included in <I>press</I> and <I>pxx</I>, <I>pyy</I>,
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etc.
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</P>
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<HR>
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<P>The <I>c_ID</I> and <I>c_ID[N]</I> keywords allow global scalar or vector
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quantities calculated by a compute to be output. The ID in the
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keyword should be replaced by the actual ID of the compute that has
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been defined elsewhere in the input script. See the
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<A HREF = "compute.html">compute</A> command for details. Note that only global
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scalar or vector quantities calculated by a compute can be output as
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thermodynamic data; per-atom quantities calcalated by a compute are
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output by the <A HREF = "dump.html">dump custom</A> command. However, there is a
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<A HREF = "compute_sum.html">compute sum</A> command which sums per-atom quantities
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into a global scalar or vector which can be output by thermo_style
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custom.
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</P>
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<P>Note that some computes calculate "intensive" global quantities like
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temperature; others calculate "extensive" global quantities like
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kinetic energy that are summed over all atoms in the compute group.
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Intensive quantities are printed directly by thermo_style custom.
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Extensive quantites may be normalized by the total number of atoms in
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the simulation (NOT the number of atoms in the compute group)
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depending on the <A HREF = "thermo_modify.html">thermo_modify norm</A> option being
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used.
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</P>
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<P>If <I>c_ID</I> is used as a keyword, then the scalar quantity calculated by
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the compute is printed. If <I>c_ID[N]</I> is used, then the compute must
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calculate a vector quantity and N must be an index from 1 to M where M
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is the length of the vector calculated by the compute. See the doc
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pages for individual compute styles for info on what these quantities
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are.
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</P>
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<P>The <I>f_ID</I> and <I>f_ID[N]</I> keywords allow global scalar or vector
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quantities calculated by a fix to be output. The ID in the keyword
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should be replaced by the actual ID of the fix that has been defined
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elsewhere in the input script. See the doc pages for individual <A HREF = "fix.html">fix
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commands</A> for details of which fixes generate global values.
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One particularly useful fix to use in this context is the <A HREF = "fix_ave_time.html">fix
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ave/time</A> command, which calculates time-averages of
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global scalar and vector quantities calculated by other
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<A HREF = "compute.html">computes</A> and <A HREF = "fix.html">fixes</A>.
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</P>
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<P>Note that some fixes calculate "intensive" global quantities like
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timestep size; others calculate "extensive" global quantities like
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energy that are summed over all atoms in the fix group. Intensive
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quantities are printed directly by thermo_style custom. Extensive
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quantites may be normalized by the total number of atoms in the
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simulation (NOT the number of atoms in the fix group) depending on the
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<A HREF = "thermo_modify.html">thermo_modify norm</A> option being used.
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</P>
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<P>If <I>f_ID</I> is used as a keyword, then the scalar quantity calculated by
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the fix is printed. If <I>f_ID[N]</I> is used, then the fix must
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calculate a vector quantity and N must be an index from 1 to M where M
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is the length of the vector calculated by the fix. See the doc pages
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for individual fix styles for info on which fixes calculate these
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global quantities and what they are. For fixes that compute a
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contribution to the potential energy of the system, the scalar
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quantity f_ID is typically that quantity.
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</P>
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<P>The <I>v_name</I> keyword allow the current value of a variable to be
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output. The name in the keyword should be replaced by the actual namd
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of the variable that has been defined elsewhere in the input script.
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See the <A HREF = "variable.html">variable</A> command for details. Equal-style
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variables can calculate complex formulas involving atom and group
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properties, mathematical operations, other variables, etc. This
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keyword enables them to be evaluated and their value printed
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periodically during a simulation.
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</P>
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<P>See <A HREF = "Section_modify.html">this section</A> for information on how to add
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new compute and fix styles as well as variable options to LAMMPS that
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calculate quantities that could then be output with these keywords as
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part of thermodyanmic information.
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</P>
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<HR>
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<P><B>Restrictions:</B>
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</P>
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<P>This command must come after the simulation box is defined by a
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<A HREF = "read_data.html">read_data</A>, <A HREF = "read_restart.html">read_restart</A>, or
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<A HREF = "create_box.html">create_box</A> command.
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</P>
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<P><B>Related commands:</B>
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</P>
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<P><A HREF = "thermo.html">thermo</A>, <A HREF = "thermo_modify.html">thermo_modify</A>,
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<A HREF = "fix_modify.html">fix_modify</A>, <A HREF = "temperature.html">temperature</A>
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</P>
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<P><B>Default:</B>
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</P>
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<PRE>thermo_style one
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</PRE>
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</HTML>
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