From cd92c5fb0c700cb0cf557de785ac0bd9bfc3ec65 Mon Sep 17 00:00:00 2001 From: sjplimp Date: Tue, 18 Mar 2008 22:21:46 +0000 Subject: [PATCH] git-svn-id: svn://svn.icms.temple.edu/lammps-ro/trunk@1627 f3b2605a-c512-4ea7-a41b-209d697bcdaa --- doc/Section_commands.html | 7 +- doc/Section_commands.txt | 1 + doc/fix.html | 1 + doc/fix.txt | 2 + doc/fix_nph.html | 30 +++--- doc/fix_nph.txt | 30 +++--- doc/fix_npt.html | 22 ++-- doc/fix_npt.txt | 22 ++-- doc/fix_press_berendsen.html | 195 +++++++++++++++++++++++++++++++++++ doc/fix_press_berendsen.txt | 183 ++++++++++++++++++++++++++++++++ 10 files changed, 442 insertions(+), 51 deletions(-) create mode 100644 doc/fix_press_berendsen.html create mode 100644 doc/fix_press_berendsen.txt diff --git a/doc/Section_commands.html b/doc/Section_commands.html index f8a81fb664..dfb7ef7034 100644 --- a/doc/Section_commands.html +++ b/doc/Section_commands.html @@ -321,9 +321,10 @@ of each style or click on the style itself for a full description: depositdragdt/resetefieldenforce2dfreezegravitygyration heatindentlangevinlineforcemsdmomentumnphnpt npt/aspherenvenve/aspherenve/limitnve/noforcenve/spherenvtnvt/asphere -nvt/sllodorient/fccplaneforcepoemspourprintrdfrecenter -rigidsetforceshakespringspring/rgspring/selftemp/berendsentemp/rescale -tmdviscosityviscouswall/granwall/lj126wall/lj93wall/reflectwiggle +nvt/sllodorient/fccplaneforcepoemspourpress/berendsenprintrdf +recenterrigidsetforceshakespringspring/rgspring/selftemp/berendsen +temp/rescaletmdviscosityviscouswall/granwall/lj126wall/lj93wall/reflect +wiggle
diff --git a/doc/Section_commands.txt b/doc/Section_commands.txt index 74ceb67202..f600d625c2 100644 --- a/doc/Section_commands.txt +++ b/doc/Section_commands.txt @@ -412,6 +412,7 @@ of each style or click on the style itself for a full description: "planeforce"_fix_planeforce.html, "poems"_fix_poems.html, "pour"_fix_pour.html, +"press/berendsen"_fix_press_berendsen.html, "print"_fix_print.html, "rdf"_fix_rdf.html, "recenter"_fix_recenter.html, diff --git a/doc/fix.html b/doc/fix.html index 9d30bb4b1e..67776ae2a2 100644 --- a/doc/fix.html +++ b/doc/fix.html @@ -140,6 +140,7 @@ list of fix styles available in LAMMPS:
  • planeforce - constrain atoms to move in a plane
  • poems - constrain clusters of atoms to move as coupled rigid bodies
  • pour - pour new atoms into a granular simulation domain +
  • press/berendsen - pressure control by Berendsen barostat
  • print - print text and variables during a simulation
  • rdf - compute radial distribution functions
  • recenter - constrain the center-of-mass position of a group of atoms diff --git a/doc/fix.txt b/doc/fix.txt index 4f8e76d742..db57749aac 100644 --- a/doc/fix.txt +++ b/doc/fix.txt @@ -140,6 +140,8 @@ list of fix styles available in LAMMPS: "poems"_fix_poems.html - constrain clusters of atoms to move \ as coupled rigid bodies "pour"_fix_pour.html - pour new atoms into a granular simulation domain +"press/berendsen"_fix_press_berendsen.html - pressure control by \ + Berendsen barostat "print"_fix_print.html - print text and variables during a simulation "rdf"_fix_rdf.html - compute radial distribution functions "recenter"_fix_recenter.html - constrain the center-of-mass position \ diff --git a/doc/fix_nph.html b/doc/fix_nph.html index 63c71e3f64..fd6fdd441f 100644 --- a/doc/fix_nph.html +++ b/doc/fix_nph.html @@ -56,8 +56,8 @@ barostat (Hoover), implemented as described in (Melchionna). P is pressure. This creates a system trajectory consistent with the isobaric ensemble. Unlike fix npt, temperature will not be controlled if no other fix -is used. Temperature can be controlled independently by using "fix -langevin or fix +is used. Temperature can be controlled independently by using a +thermostatting fis such as fix langevin or fix temp/rescale.

    The atoms in the fix group are the only ones whose velocities and @@ -72,6 +72,15 @@ only the atoms in the fix group are re-scaled. The latter can be useful for leaving the coordinates of atoms in a solid substrate unchanged and controlling the pressure of a surrounding fluid.

    +

    IMPORTANT NOTE: Unlike the fix +press/berendsen command which performs +barostatting but NO time integration, this fix performs barostatting +AND time integration. Thus you should not use any other time +integration fix, such as fix nve or fix +nvt on atoms to which this fix is applied. Use fix +npt instead of this fix, if you want to control both +temperature and pressure via Nose/Hoover. +

    The pressure can be controlled in one of several styles, as specified @@ -112,14 +121,13 @@ Typically a value between 0.2 to 2.0 is sufficient to damp oscillations after a few periods.

    For all pressure styles, the simulation box stays rectangular in -shape. Parinello-Rahman boundary conditions (tilted box) are not -implemented in LAMMPS. +shape. Parinello-Rahman boundary conditions (tilted box) for this fix +are not yet implemented in LAMMPS.

    -

    For all styles, the Pdamp parameter operates like the Tdamp -parameter, determining the time scale on which pressure is relaxed. -For example, a value of 1000.0 means to relax the pressure in a -timespan of (roughly) 1000 time units (tau or fmsec or psec - see the -units command). +

    For all styles, the Pdamp parameter determines the time scale on +which pressure is relaxed. For example, a value of 1000.0 means to +relax the pressure in a timespan of (roughly) 1000 time units (tau or +fmsec or psec - see the units command).

    @@ -187,10 +195,6 @@ the simulation. dimension whose target pressures are specified as NULL can be non-periodic or periodic.

    -

    You should not use fix nvt with this fix. Instead, use -fix npt if you want to control both temperature and -pressure via Nose/Hoover. -

    Related commands:

    fix nve, fix npt, diff --git a/doc/fix_nph.txt b/doc/fix_nph.txt index bcc1731846..0cc8e5e671 100644 --- a/doc/fix_nph.txt +++ b/doc/fix_nph.txt @@ -47,8 +47,8 @@ barostat "(Hoover)"_#Hoover, implemented as described in "(Melchionna)"_#Melchionna. P is pressure. This creates a system trajectory consistent with the isobaric ensemble. Unlike "fix npt"_fix_npt.html, temperature will not be controlled if no other fix -is used. Temperature can be controlled independently by using ""fix -langevin"_fix_langevin.html or "fix +is used. Temperature can be controlled independently by using a +thermostatting fis such as "fix langevin"_fix_langevin.html or "fix temp/rescale"_fix_temp_rescale.html. The atoms in the fix group are the only ones whose velocities and @@ -63,6 +63,15 @@ only the atoms in the fix group are re-scaled. The latter can be useful for leaving the coordinates of atoms in a solid substrate unchanged and controlling the pressure of a surrounding fluid. +IMPORTANT NOTE: Unlike the "fix +press/berendsen"_fix_press_berendsen.html command which performs +barostatting but NO time integration, this fix performs barostatting +AND time integration. Thus you should not use any other time +integration fix, such as "fix nve"_fix_nve.html or "fix +nvt"_fix_nvt.html on atoms to which this fix is applied. Use "fix +npt"_fix_npt.html instead of this fix, if you want to control both +temperature and pressure via Nose/Hoover. + :line The pressure can be controlled in one of several styles, as specified @@ -103,14 +112,13 @@ Typically a value between 0.2 to 2.0 is sufficient to damp oscillations after a few periods. For all pressure styles, the simulation box stays rectangular in -shape. Parinello-Rahman boundary conditions (tilted box) are not -implemented in LAMMPS. +shape. Parinello-Rahman boundary conditions (tilted box) for this fix +are not yet implemented in LAMMPS. -For all styles, the {Pdamp} parameter operates like the {Tdamp} -parameter, determining the time scale on which pressure is relaxed. -For example, a value of 1000.0 means to relax the pressure in a -timespan of (roughly) 1000 time units (tau or fmsec or psec - see the -"units"_units.html command). +For all styles, the {Pdamp} parameter determines the time scale on +which pressure is relaxed. For example, a value of 1000.0 means to +relax the pressure in a timespan of (roughly) 1000 time units (tau or +fmsec or psec - see the "units"_units.html command). :line @@ -177,10 +185,6 @@ Any dimension being adjusted by this fix must be periodic. A dimension whose target pressures are specified as NULL can be non-periodic or periodic. -You should not use "fix nvt"_fix_nvt.html with this fix. Instead, use -"fix npt"_fix_npt.html if you want to control both temperature and -pressure via Nose/Hoover. - [Related commands:] "fix nve"_fix_nve.html, "fix npt"_fix_npt.html, diff --git a/doc/fix_npt.html b/doc/fix_npt.html index b806b95384..6c099d2763 100644 --- a/doc/fix_npt.html +++ b/doc/fix_npt.html @@ -77,15 +77,15 @@ only the atoms in the fix group are re-scaled. The latter can be useful for leaving the coordinates of atoms in a solid substrate unchanged and controlling the pressure of a surrounding fluid.

    -

    IMPORTANT NOTE: Unlike the fix temp/berendsen -command which performs thermostatting but NO time integration, this -fix performs thermostatting/barostatting AND time integration. Thus -you should not use any other time integration fix, such as fix -nve on atoms to which this fix is applied. Likewise, -this fix should not normally be used on atoms that also have their -temperature controlled by another fix - e.g. by fix -langevin or fix temp/rescale -commands. +

    IMPORTANT NOTE: Unlike the fix +temp/berendsen command which performs +thermostatting but NO time integration, this fix performs +thermostatting/barostatting AND time integration. Thus you should not +use any other time integration fix, such as fix nve on +atoms to which this fix is applied. Likewise, this fix should not +normally be used on atoms that also have their temperature controlled +by another fix - e.g. by fix langevin or fix +temp/rescale commands.

    @@ -127,8 +127,8 @@ is working. Typically a value between 0.2 to 2.0 is sufficient to damp oscillations after a few periods.

    For all pressure styles, the simulation box stays rectangular in -shape. Parinello-Rahman boundary conditions (tilted box) are not yet -implemented in LAMMPS. +shape. Parinello-Rahman boundary conditions (tilted box) for this fix +are not yet implemented in LAMMPS.

    For all styles, the Pdamp parameter operates like the Tdamp parameter, determining the time scale on which pressure is relaxed. diff --git a/doc/fix_npt.txt b/doc/fix_npt.txt index 761c8e0d12..8244edc553 100644 --- a/doc/fix_npt.txt +++ b/doc/fix_npt.txt @@ -66,15 +66,15 @@ only the atoms in the fix group are re-scaled. The latter can be useful for leaving the coordinates of atoms in a solid substrate unchanged and controlling the pressure of a surrounding fluid. -IMPORTANT NOTE: Unlike the "fix temp/berendsen"_fix_berendsen.html -command which performs thermostatting but NO time integration, this -fix performs thermostatting/barostatting AND time integration. Thus -you should not use any other time integration fix, such as "fix -nve"_fix_nve.html on atoms to which this fix is applied. Likewise, -this fix should not normally be used on atoms that also have their -temperature controlled by another fix - e.g. by "fix -langevin"_fix_nvt.html or "fix temp/rescale"_fix_temp_rescale.html -commands. +IMPORTANT NOTE: Unlike the "fix +temp/berendsen"_fix_temp_berendsen.html command which performs +thermostatting but NO time integration, this fix performs +thermostatting/barostatting AND time integration. Thus you should not +use any other time integration fix, such as "fix nve"_fix_nve.html on +atoms to which this fix is applied. Likewise, this fix should not +normally be used on atoms that also have their temperature controlled +by another fix - e.g. by "fix langevin"_fix_nvt.html or "fix +temp/rescale"_fix_temp_rescale.html commands. :line @@ -116,8 +116,8 @@ is working. Typically a value between 0.2 to 2.0 is sufficient to damp oscillations after a few periods. For all pressure styles, the simulation box stays rectangular in -shape. Parinello-Rahman boundary conditions (tilted box) are not yet -implemented in LAMMPS. +shape. Parinello-Rahman boundary conditions (tilted box) for this fix +are not yet implemented in LAMMPS. For all styles, the {Pdamp} parameter operates like the {Tdamp} parameter, determining the time scale on which pressure is relaxed. diff --git a/doc/fix_press_berendsen.html b/doc/fix_press_berendsen.html new file mode 100644 index 0000000000..7141495304 --- /dev/null +++ b/doc/fix_press_berendsen.html @@ -0,0 +1,195 @@ + +

    LAMMPS WWW Site - LAMMPS Documentation - LAMMPS Commands +
    + + + + + + +
    + +

    fix press/berendsen command +

    +

    Syntax: +

    +
    fix ID group-ID press/berendsen p-style args keyword value ... 
+
    + +

    Examples: +

    +
    fix 1 all press/berendsen xyz 0.0 0.0 1000.0
+fix 2 all press/berendsen aniso 0.0 0.0 0.0 0.0 NULL NULL 1000.0 dilate partial 
+
    +

    Description: +

    +

    Reset the pressure of the system by using a Berendsen barostat +(Berendsen), which rescales the system volume and +(optionally) the atoms coordinates withing the simulation box every +timestep. +

    +

    Regardless of what atoms are in the fix group, a global pressure is +computed for all atoms. Similarly, when the size of the simulation +box is changed, all atoms are re-scaled to new positions, unless the +keyword dilate is specified with a value of partial, in which case +only the atoms in the fix group are re-scaled. The latter can be +useful for leaving the coordinates of atoms in a solid substrate +unchanged and controlling the pressure of a surrounding fluid. +

    +

    IMPORTANT NOTE: Unlike the fix npt or fix +nph commands which perform Nose/Hoover barostatting AND +time integration, this fix does NOT perform time integration. It only +modifies the box size and atom coordinates to effect barostatting. +Thus you must use a separate time integration fix, like fix +nve or fix nvt to actually update the +positions and velocities of atoms. This fix can be used in +conjunction with thermostatting fixes to control the temperature, such +as fix nvt or fix langevin or fix +temp/berendsen. +

    +
    + +

    The pressure can be controlled in one of several styles, as specified +by the p-style argument. In each case, the desired pressure at each +timestep is a ramped value during the run from the starting value to +the end value. +

    +

    Style xyz means couple all dimensions together when pressure is +computed (isotropic pressure), and dilate/contract the dimensions +together. +

    +

    Styles xy or yz or xz means that the 2 specified dimensions are +coupled together, both for pressure computation and for +dilation/contraction. The 3rd dimension dilates/contracts +independently, using its pressure component as the driving force. +These styles cannot be used for a 2d simulation. +

    +

    For style aniso, all dimensions dilate/contract independently using +their individual pressure components as the driving forces. +

    +

    For any of the styles except xyz, any of the independent pressure +components (e.g. z in xy, or any dimension in aniso) can have +their target pressures (both start and stop values) specified as NULL. +This means that no pressure control is applied to that dimension so +that the box dimension remains unchanged. For a 2d simulation the z +pressure components must be specified as NULL when using style +aniso. +

    +

    In some cases (e.g. for solids) the pressure (volume) and/or +temperature of the system can oscillate undesirably when a Nose/Hoover +barostat is applied. The optional drag keyword will damp these +oscillations, although it alters the Nose/Hoover equations. A value +of 0.0 (no drag) leaves the Nose/Hoover formalism unchanged. A +non-zero value adds a drag term; the larger the value specified, the +greater the damping effect. Performing a short run and monitoring the +pressure is the best way to determine if the drag term is working. +Typically a value between 0.2 to 2.0 is sufficient to damp +oscillations after a few periods. +

    +

    For all pressure styles, the simulation box stays rectangular in +shape. Parinello-Rahman boundary conditions (tilted box) for this fix +are not yet implemented in LAMMPS. +

    +

    For all styles, the Pdamp parameter determines the time scale on +which pressure is relaxed. For example, a value of 1000.0 means to +relax the pressure in a timespan of (roughly) 1000 time units (tau or +fmsec or psec - see the units command). +

    +
    + +

    This fix computes a temperature and pressure each timestep. To do +this, the fix creates its own computes of style "temp" and "pressure", +as if these commands had been issued: +

    +
    compute fix-ID_temp group-ID temp 
+
    +
    compute fix-ID_press group-ID pressure fix-ID_temp 
+
    +

    See the compute temp and compute +pressure commands for details. Note that the +IDs of the new computes are the fix-ID + underscore + "temp" or fix_ID ++ underscore + "press", and the group for the new computes is the same +as the fix group. +

    +

    Note that these are NOT the computes used by thermodynamic output (see +the thermo_style command) with ID = thermo_temp +and thermo_press. This means you can change the attributes of this +fix's temperature or pressure via the +compute_modify command or print this temperature +or pressure during thermodynamic output via the thermo_style +custom command using the appropriate compute-ID. +It also means that changing attributes of thermo_temp or +thermo_press will have no effect on this fix. +

    +

    Restart, fix_modify, output, run start/stop, minimize info: +

    +

    No information about this fix is written to binary restart +files. +

    +

    The fix_modify temp and press options are +supported by this fix. You can use them to assign a +compute you have defined to this fix which will be used +in its temperature and pressure calculations. If you do this, note +that the kinetic energy derived from the compute temperature should be +consistent with the virial term computed using all atoms for the +pressure. LAMMPS will warn you if you choose to compute temperature +on a subset of atoms. +

    +

    No global scalar or vector or per-atom quantities are stored by this +fix for access by various output commands. +

    +

    This fix can ramp its target pressure over multiple runs, using the +start and stop keywords of the run command. See the +run command for details of how to do this. +

    +

    This fix is not invoked during energy minimization. +

    +

    Restrictions: +

    +

    Any dimension being adjusted by this fix must be periodic. A +dimension whose target pressures are specified as NULL can be +non-periodic or periodic. +

    +

    Related commands: +

    +

    fix nve, fix nph, fix +npt, fix temp/berendsen, +fix_modify +

    +

    Default: +

    +

    The keyword defaults are dilate = all. +

    +
    + + + +

    (Berendsen) Berendsen, Postma, van Gunsteren, DiNola, Haak, J Chem +Phys, 81, 3684 (1984). +

    + diff --git a/doc/fix_press_berendsen.txt b/doc/fix_press_berendsen.txt new file mode 100644 index 0000000000..b4368bf692 --- /dev/null +++ b/doc/fix_press_berendsen.txt @@ -0,0 +1,183 @@ +"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 + +fix press/berendsen command :h3 + +[Syntax:] + +fix ID group-ID press/berendsen p-style args keyword value ... :pre + +ID, group-ID are documented in "fix"_fix.html command :ulb,l +press/berendsen = style name of this fix command :l +p-style = {xyz} or {xy} or {yz} or {xz} or {aniso} :l + {xyz} args = Pstart Pstop Pdamp + Pstart,Pstop = desired pressure at start/end of run (pressure units) + Pdamp = pressure damping parameter (time units) + {xy} or {yz} or {xz} args = Px0 Px1 Py0 Py1 Pz0 Pz1 Pdamp + Px0,Px1,Py0,Py1,Pz0,Pz1 = desired pressure in x,y,z at + start/end (0/1) of run (pressure units) + Pdamp = pressure damping parameter (time units) + {aniso} args = Px0 Px1 Py0 Py1 Pz0 Pz1 Pdamp + Px0,Px1,Py0,Py1,Pz0,Pz1 = desired pressure in x,y,z at + start/end (0/1) of run (pressure units) + Pdamp = pressure damping parameter (time units) :pre + +zero or more keyword/value pairs may be appended :l +keyword = {dilate} :l + {dilate} value = {all} or {partial} :pre +:ule + +[Examples:] + +fix 1 all press/berendsen xyz 0.0 0.0 1000.0 +fix 2 all press/berendsen aniso 0.0 0.0 0.0 0.0 NULL NULL 1000.0 dilate partial :pre + +[Description:] + +Reset the pressure of the system by using a Berendsen barostat +"(Berendsen)"_#Berendsen, which rescales the system volume and +(optionally) the atoms coordinates withing the simulation box every +timestep. + +Regardless of what atoms are in the fix group, a global pressure is +computed for all atoms. Similarly, when the size of the simulation +box is changed, all atoms are re-scaled to new positions, unless the +keyword {dilate} is specified with a value of {partial}, in which case +only the atoms in the fix group are re-scaled. The latter can be +useful for leaving the coordinates of atoms in a solid substrate +unchanged and controlling the pressure of a surrounding fluid. + +IMPORTANT NOTE: Unlike the "fix npt"_fix_npt.html or "fix +nph"_fix_nph.html commands which perform Nose/Hoover barostatting AND +time integration, this fix does NOT perform time integration. It only +modifies the box size and atom coordinates to effect barostatting. +Thus you must use a separate time integration fix, like "fix +nve"_fix_nve.html or "fix nvt"_fix_nvt.html to actually update the +positions and velocities of atoms. This fix can be used in +conjunction with thermostatting fixes to control the temperature, such +as "fix nvt"_fix_nvt.html or "fix langevin"_fix_langevin.html or "fix +temp/berendsen"_fix_temp_berendsen,html. + +:line + +The pressure can be controlled in one of several styles, as specified +by the {p-style} argument. In each case, the desired pressure at each +timestep is a ramped value during the run from the starting value to +the end value. + +Style {xyz} means couple all dimensions together when pressure is +computed (isotropic pressure), and dilate/contract the dimensions +together. + +Styles {xy} or {yz} or {xz} means that the 2 specified dimensions are +coupled together, both for pressure computation and for +dilation/contraction. The 3rd dimension dilates/contracts +independently, using its pressure component as the driving force. +These styles cannot be used for a 2d simulation. + +For style {aniso}, all dimensions dilate/contract independently using +their individual pressure components as the driving forces. + +For any of the styles except {xyz}, any of the independent pressure +components (e.g. z in {xy}, or any dimension in {aniso}) can have +their target pressures (both start and stop values) specified as NULL. +This means that no pressure control is applied to that dimension so +that the box dimension remains unchanged. For a 2d simulation the z +pressure components must be specified as NULL when using style +{aniso}. + +In some cases (e.g. for solids) the pressure (volume) and/or +temperature of the system can oscillate undesirably when a Nose/Hoover +barostat is applied. The optional {drag} keyword will damp these +oscillations, although it alters the Nose/Hoover equations. A value +of 0.0 (no drag) leaves the Nose/Hoover formalism unchanged. A +non-zero value adds a drag term; the larger the value specified, the +greater the damping effect. Performing a short run and monitoring the +pressure is the best way to determine if the drag term is working. +Typically a value between 0.2 to 2.0 is sufficient to damp +oscillations after a few periods. + +For all pressure styles, the simulation box stays rectangular in +shape. Parinello-Rahman boundary conditions (tilted box) for this fix +are not yet implemented in LAMMPS. + +For all styles, the {Pdamp} parameter determines the time scale on +which pressure is relaxed. For example, a value of 1000.0 means to +relax the pressure in a timespan of (roughly) 1000 time units (tau or +fmsec or psec - see the "units"_units.html command). + +:line + +This fix computes a temperature and pressure each timestep. To do +this, the fix creates its own computes of style "temp" and "pressure", +as if these commands had been issued: + +compute fix-ID_temp group-ID temp :pre +compute fix-ID_press group-ID pressure fix-ID_temp :pre + +See the "compute temp"_compute_temp.html and "compute +pressure"_compute_pressure.html commands for details. Note that the +IDs of the new computes are the fix-ID + underscore + "temp" or fix_ID ++ underscore + "press", and the group for the new computes is the same +as the fix group. + +Note that these are NOT the computes used by thermodynamic output (see +the "thermo_style"_thermo_style.html command) with ID = {thermo_temp} +and {thermo_press}. This means you can change the attributes of this +fix's temperature or pressure via the +"compute_modify"_compute_modify.html command or print this temperature +or pressure during thermodynamic output via the "thermo_style +custom"_thermo_style.html command using the appropriate compute-ID. +It also means that changing attributes of {thermo_temp} or +{thermo_press} will have no effect on this fix. + +[Restart, fix_modify, output, run start/stop, minimize info:] + +No information about this fix is written to "binary restart +files"_restart.html. + +The "fix_modify"_fix_modify.html {temp} and {press} options are +supported by this fix. You can use them to assign a +"compute"_compute.html you have defined to this fix which will be used +in its temperature and pressure calculations. If you do this, note +that the kinetic energy derived from the compute temperature should be +consistent with the virial term computed using all atoms for the +pressure. LAMMPS will warn you if you choose to compute temperature +on a subset of atoms. + +No global scalar or vector or per-atom quantities are stored by this +fix for access by various "output commands"_Section_howto.html#4_15. + +This fix can ramp its target pressure over multiple runs, using the +{start} and {stop} keywords of the "run"_run.html command. See the +"run"_run.html command for details of how to do this. + +This fix is not invoked during "energy minimization"_minimize.html. + +[Restrictions:] + +Any dimension being adjusted by this fix must be periodic. A +dimension whose target pressures are specified as NULL can be +non-periodic or periodic. + +[Related commands:] + +"fix nve"_fix_nve.html, "fix nph"_fix_nph.html, "fix +npt"_fix_npt.html, "fix temp/berendsen"_fix_temp_berendsen.html, +"fix_modify"_fix_modify.html + +[Default:] + +The keyword defaults are dilate = all. + +:line + +:link(Berendsen) + +[(Berendsen)] Berendsen, Postma, van Gunsteren, DiNola, Haak, J Chem +Phys, 81, 3684 (1984).