forked from lijiext/lammps
265 lines
12 KiB
Plaintext
265 lines
12 KiB
Plaintext
"LAMMPS WWW Site"_lws - "LAMMPS Documentation"_ld - "LAMMPS Commands"_lc :c
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:link(lws,http://lammps.sandia.gov)
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:link(ld,Manual.html)
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:link(lc,Section_commands.html#comm)
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:line
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thermo_style command :h3
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[Syntax:]
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thermo_style style args :pre
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style = {one} or {multi} or {custom} :ulb,l
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args = list of arguments for a particular style :l
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{one} args = none
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{multi} args = none
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{custom} 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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xy, xz, yz,
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pxx, pyy, pzz, pxy, pxz, pyz,
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c_ID, c_ID\[I\], c_ID\[I\]\[J\],
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f_ID, f_ID\[I\], f_ID\[I\]\[J\],
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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 (etotal + 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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xy,xz,yz = box tilt for triclinic (non-orthogonal) simulation boxes
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pxx,pyy,pzz,pxy,pxz,pyz = 6 components of pressure tensor
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c_ID = global scalar value calculated by a compute with ID
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c_ID\[I\] = Ith component of global vector calculated by a compute with ID
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c_ID\[I\]\[J\] = I,J component of global array calculated by a compute with ID
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f_ID = global scalar value calculated by a fix with ID
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f_ID\[I\] = Ith component of global vector calculated by a fix with ID
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f_ID\[I\]\[J\] = I,J component of global array calculated by a fix with ID
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v_name = scalar value calculated by an equal-style variable with name :pre
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:ule
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[Examples:]
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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 :pre
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[Description:]
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Set the style and content for printing thermodynamic data to the
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screen and log file.
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Style {one} 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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Style {multi} 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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Style {custom} 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 "computes"_compute.html, "fixes"_fix.html, and
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equal-style "variables"_variable.html" that have been defined
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elsewhere in the input script or can even be new styles which users
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have added to LAMMPS (see the "Section_modify"_Section_modify.html
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section of the documentation). Thus the {custom} style provides a
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flexible means of outputting essentially any desired quantity as a
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simulation proceeds.
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All styles except {custom} have {vol} appended to their list of
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outputs if the simulation box volume changes during the simulation.
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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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"fix ave/time"_fix_ave_time.html command.
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Options invoked by the "thermo_modify"_thermo_modify.html 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 thermodynamic output (total values versus per-atom
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values for extensive quantities (ones which scale with the number of
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atoms in the system), and the numeric precision of each printed value.
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IMPORTANT NOTE: When you use a "thermo_style" 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"_thermo_modify.html 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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:line
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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 a {temperature} compute which is created
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when LAMMPS starts up, as if this command had been issued:
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compute thermo_temp all temp :pre
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See the "compute temp"_compute_temp.html command for details. Note
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that the ID of this compute is {thermo_temp} and the group is {all}.
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You can change the attributes of this temperature (e.g. its
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degrees-of-freedom) via the "compute_modify"_compute_modify.html
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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 "thermo_modify"_thermo_modify.html command.
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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 a {pressure} compute which is created when LAMMPS starts up, as
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if this command had been issued:
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compute thermo_press all pressure thermo_temp :pre
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See the "compute pressure"_compute_pressure.html command for details.
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Note that the ID of this compute is {thermo_press} and the group is
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{all}. You can change the attributes of this pressure via the
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"compute_modify"_compute_modify.html 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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"thermo_modify"_thermo_modify.html command.
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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 a
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{pe} compute which is created when LAMMPS starts up, as if this
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command had been issued:
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compute thermo_pe all pe :pre
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See the "compute pe"_compute_pe.html command for details. Note that
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the ID of this compute is {thermo_pe} and the group is {all}. You can
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change the attributes of this potential energy via the
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"compute_modify"_compute_modify.html command.
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:line
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The kinetic energy of the system {ke} is inferred from the temperature
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of the system with 1/2 Kb T of energy for each degree of freedom.
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Thus, using different "compute commands"_compute.html for calculating
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temperature, via the "thermo_modify temp"_thermo_modify.html command,
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may yield different kinetic energies, since different computes that
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calculate temperature can subtract out different non-thermal
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components of velocity and/or include different degrees of freedom
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(translational, rotational, etc).
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The potential energy of the system {pe} will include contributions
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from fixes if the "fix_modify thermo"_fix_modify.html option is set
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for a fix that calculates such a contribution. For example, the "fix
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wall/lj93"_fix_wall_lj93 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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A long-range tail correction {etail} for the VanderWaal pairwise
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energy will be non-zero only if the "pair_modify
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tail"_pair_modify.html option is turned on. The {etail} contribution
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is included in {evdwl}, {pe}, and {etotal}, and the corresponding tail
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correction to the pressure is included in {press} and {pxx}, {pyy},
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etc.
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:line
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The {c_ID} and {c_ID\[I\]} and {c_ID\[I\]\[J\]} keywords allow global
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values calculated by a compute to be output. As discussed on the
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"compute"_compute.html doc page, computes can calculate global,
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per-atom, or local values. Only global values can be referenced by
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this command. However, per-atom compute values can be referenced in a
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"variable"_variable.html and the variable referenced by thermo_style
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custom, as discussed below.
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The ID in the keyword should be replaced by the actual ID of a compute
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that has been defined elsewhere in the input script. See the
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"compute"_compute.html command for details. If the compute calculates
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a global scalar, vector, or array, then the keyword formats with 0, 1,
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or 2 brackets will reference a scalar value from the compute.
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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 without normalization by
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thermo_style custom. Extensive quantities may be normalized by the
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total number of atoms in the simulation (NOT the number of atoms in
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the compute group) when output, depending on the "thermo_modify
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norm"_thermo_modify.html option being used.
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The {f_ID} and {f_ID\[I\]} and {f_ID\[I\]\[J\]} keywords allow global
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values calculated by a fix to be output. As discussed on the
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"fix"_fix.html doc page, fixes can calculate global, per-atom, or
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local values. Only global values can be referenced by this command.
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However, per-atom fix values can be referenced in a
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"variable"_variable.html and the variable referenced by thermo_style
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custom, as discussed below.
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The ID in the keyword should be replaced by the actual ID of a fix
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that has been defined elsewhere in the input script. See the
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"fix"_fix.html command for details. If the fix calculates a global
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scalar, vector, or array, then the keyword formats with 0, 1, or 2
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brackets will reference a scalar value from the fix.
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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 without normalization by thermo_style
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custom. Extensive quantities may be normalized by the total number of
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atoms in the simulation (NOT the number of atoms in the fix group)
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when output, depending on the "thermo_modify norm"_thermo_modify.html
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option being used.
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The {v_name} 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 name
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of the variable that has been defined elsewhere in the input script.
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Only equal-style variables can be referenced. See the
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"variable"_variable.html command for details. Variables of style
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{equal} can reference per-atom properties or thermodynamic keywords,
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or they can invoke other computes, fixes, or variables when evaluated,
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so this is a very general means of creating thermodynamic output.
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See "this section"_Section_modify.html for information on how to add
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new compute and fix styles to LAMMPS to calculate quantities that can
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then be referenced with these keywords to generate thermodynamic
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output.
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:line
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[Restrictions:]
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This command must come after the simulation box is defined by a
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"read_data"_read_data.html, "read_restart"_read_restart.html, or
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"create_box"_create_box.html command.
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[Related commands:]
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"thermo"_thermo.html, "thermo_modify"_thermo_modify.html,
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"fix_modify"_fix_modify.html, "compute temp"_compute_temp.html,
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"compute pressure"_compute_pressure.html
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[Default:]
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thermo_style one :pre
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