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463 lines
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<li class="toctree-l1"><a class="reference internal" href="Section_intro.html">1. Introduction</a></li>
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<li class="toctree-l1"><a class="reference internal" href="Section_start.html">2. Getting Started</a></li>
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<li class="toctree-l1"><a class="reference internal" href="Section_commands.html">3. Commands</a></li>
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<li class="toctree-l1"><a class="reference internal" href="Section_accelerate.html">5. Accelerating LAMMPS performance</a></li>
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<li class="toctree-l1"><a class="reference internal" href="Section_howto.html">6. How-to discussions</a></li>
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<li class="toctree-l1"><a class="reference internal" href="Section_example.html">7. Example problems</a></li>
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<li class="toctree-l1"><a class="reference internal" href="Section_perf.html">8. Performance & scalability</a></li>
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<li class="toctree-l1"><a class="reference internal" href="Section_modify.html">10. Modifying & extending LAMMPS</a></li>
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<li class="toctree-l1"><a class="reference internal" href="Section_python.html">11. Python interface to LAMMPS</a></li>
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<li class="toctree-l1"><a class="reference internal" href="Section_errors.html">12. Errors</a></li>
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<li class="toctree-l1"><a class="reference internal" href="Section_history.html">13. Future and history</a></li>
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<li>fix command</li>
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<div class="section" id="fix-command">
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<span id="index-0"></span><h1>fix command</h1>
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<div class="section" id="syntax">
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<h2>Syntax</h2>
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<div class="highlight-default"><div class="highlight"><pre><span></span><span class="n">fix</span> <span class="n">ID</span> <span class="n">group</span><span class="o">-</span><span class="n">ID</span> <span class="n">style</span> <span class="n">args</span>
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</pre></div>
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</div>
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<ul class="simple">
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<li>ID = user-assigned name for the fix</li>
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<li>group-ID = ID of the group of atoms to apply the fix to</li>
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<li>style = one of a long list of possible style names (see below)</li>
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<li>args = arguments used by a particular style</li>
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</ul>
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</div>
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<div class="section" id="examples">
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<h2>Examples</h2>
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<div class="highlight-default"><div class="highlight"><pre><span></span><span class="n">fix</span> <span class="mi">1</span> <span class="nb">all</span> <span class="n">nve</span>
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<span class="n">fix</span> <span class="mi">3</span> <span class="nb">all</span> <span class="n">nvt</span> <span class="n">temp</span> <span class="mf">300.0</span> <span class="mf">300.0</span> <span class="mf">0.01</span>
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<span class="n">fix</span> <span class="n">mine</span> <span class="n">top</span> <span class="n">setforce</span> <span class="mf">0.0</span> <span class="n">NULL</span> <span class="mf">0.0</span>
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</pre></div>
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</div>
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</div>
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<div class="section" id="description">
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<h2>Description</h2>
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<p>Set a fix that will be applied to a group of atoms. In LAMMPS, a
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“fix” is any operation that is applied to the system during
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timestepping or minimization. Examples include updating of atom
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positions and velocities due to time integration, controlling
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temperature, applying constraint forces to atoms, enforcing boundary
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conditions, computing diagnostics, etc. There are dozens of fixes
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defined in LAMMPS and new ones can be added; see <a class="reference internal" href="Section_modify.html"><span class="doc">this section</span></a> for a discussion.</p>
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<p>Fixes perform their operations at different stages of the timestep.
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If 2 or more fixes operate at the same stage of the timestep, they are
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invoked in the order they were specified in the input script.</p>
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<p>The ID of a fix can only contain alphanumeric characters and
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underscores.</p>
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<p>Fixes can be deleted with the <a class="reference internal" href="unfix.html"><span class="doc">unfix</span></a> command.</p>
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<div class="admonition note">
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<p class="first admonition-title">Note</p>
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<p class="last">The <a class="reference internal" href="unfix.html"><span class="doc">unfix</span></a> command is the only way to turn off a
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fix; simply specifying a new fix with a similar style will not turn
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off the first one. This is especially important to realize for
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integration fixes. For example, using a <a class="reference internal" href="fix_nve.html"><span class="doc">fix nve</span></a>
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command for a second run after using a <a class="reference internal" href="fix_nh.html"><span class="doc">fix nvt</span></a> command
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for the first run, will not cancel out the NVT time integration
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invoked by the “fix nvt” command. Thus two time integrators would be
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in place!</p>
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</div>
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<p>If you specify a new fix with the same ID and style as an existing
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fix, the old fix is deleted and the new one is created (presumably
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with new settings). This is the same as if an “unfix” command were
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first performed on the old fix, except that the new fix is kept in the
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same order relative to the existing fixes as the old one originally
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was. Note that this operation also wipes out any additional changes
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made to the old fix via the <a class="reference internal" href="fix_modify.html"><span class="doc">fix_modify</span></a> command.</p>
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<p>The <a class="reference internal" href="fix_modify.html"><span class="doc">fix modify</span></a> command allows settings for some
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fixes to be reset. See the doc page for individual fixes for details.</p>
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<p>Some fixes store an internal “state” which is written to binary
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restart files via the <a class="reference internal" href="restart.html"><span class="doc">restart</span></a> or
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<a class="reference internal" href="write_restart.html"><span class="doc">write_restart</span></a> commands. This allows the fix to
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continue on with its calculations in a restarted simulation. See the
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<a class="reference internal" href="read_restart.html"><span class="doc">read_restart</span></a> command for info on how to re-specify
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a fix in an input script that reads a restart file. See the doc pages
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for individual fixes for info on which ones can be restarted.</p>
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<hr class="docutils" />
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<p>Some fixes calculate one of three styles of quantities: global,
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per-atom, or local, which can be used by other commands or output as
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described below. A global quantity is one or more system-wide values,
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e.g. the energy of a wall interacting with particles. A per-atom
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quantity is one or more values per atom, e.g. the displacement vector
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for each atom since time 0. Per-atom values are set to 0.0 for atoms
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not in the specified fix group. Local quantities are calculated by
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each processor based on the atoms it owns, but there may be zero or
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more per atoms.</p>
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<p>Note that a single fix may produces either global or per-atom or local
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quantities (or none at all), but never more than one of these.</p>
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<p>Global, per-atom, and local quantities each come in three kinds: a
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single scalar value, a vector of values, or a 2d array of values. The
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doc page for each fix describes the style and kind of values it
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produces, e.g. a per-atom vector. Some fixes produce more than one
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kind of a single style, e.g. a global scalar and a global vector.</p>
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<p>When a fix quantity is accessed, as in many of the output commands
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discussed below, it can be referenced via the following bracket
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notation, where ID is the ID of the fix:</p>
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<table border="1" class="docutils">
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<colgroup>
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<col width="21%" />
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<col width="79%" />
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</colgroup>
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<tbody valign="top">
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<tr class="row-odd"><td>f_ID</td>
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<td>entire scalar, vector, or array</td>
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</tr>
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<tr class="row-even"><td>f_ID[I]</td>
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<td>one element of vector, one column of array</td>
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</tr>
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<tr class="row-odd"><td>f_ID[I][J]</td>
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<td>one element of array</td>
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</tr>
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</tbody>
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</table>
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<p>In other words, using one bracket reduces the dimension of the
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quantity once (vector -> scalar, array -> vector). Using two brackets
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reduces the dimension twice (array -> scalar). Thus a command that
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uses scalar fix values as input can also process elements of a vector
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or array.</p>
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<p>Note that commands and <a class="reference internal" href="variable.html"><span class="doc">variables</span></a> which use fix
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quantities typically do not allow for all kinds, e.g. a command may
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require a vector of values, not a scalar. This means there is no
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ambiguity about referring to a fix quantity as f_ID even if it
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produces, for example, both a scalar and vector. The doc pages for
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various commands explain the details.</p>
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<hr class="docutils" />
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<p>In LAMMPS, the values generated by a fix can be used in several ways:</p>
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<ul class="simple">
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<li>Global values can be output via the <a class="reference internal" href="thermo_style.html"><span class="doc">thermo_style custom</span></a> or <a class="reference internal" href="fix_ave_time.html"><span class="doc">fix ave/time</span></a> command.
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Or the values can be referenced in a <a class="reference internal" href="variable.html"><span class="doc">variable equal</span></a> or
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<a class="reference internal" href="variable.html"><span class="doc">variable atom</span></a> command.</li>
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<li>Per-atom values can be output via the <a class="reference internal" href="dump.html"><span class="doc">dump custom</span></a> command
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or the <a class="reference internal" href="fix_ave_spatial.html"><span class="doc">fix ave/spatial</span></a> command. Or they can be
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time-averaged via the <a class="reference internal" href="fix_ave_atom.html"><span class="doc">fix ave/atom</span></a> command or
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reduced by the <a class="reference internal" href="compute_reduce.html"><span class="doc">compute reduce</span></a> command. Or the
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per-atom values can be referenced in an <a class="reference internal" href="variable.html"><span class="doc">atom-style variable</span></a>.</li>
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<li>Local values can be reduced by the <a class="reference internal" href="compute_reduce.html"><span class="doc">compute reduce</span></a> command, or histogrammed by the <a class="reference internal" href="fix_ave_histo.html"><span class="doc">fix ave/histo</span></a> command.</li>
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</ul>
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<p>See this <a class="reference internal" href="Section_howto.html#howto-15"><span class="std std-ref">howto section</span></a> for a summary of
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various LAMMPS output options, many of which involve fixes.</p>
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<p>The results of fixes that calculate global quantities can be either
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“intensive” or “extensive” values. Intensive means the value is
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independent of the number of atoms in the simulation,
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e.g. temperature. Extensive means the value scales with the number of
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atoms in the simulation, e.g. total rotational kinetic energy.
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<a class="reference internal" href="thermo_style.html"><span class="doc">Thermodynamic output</span></a> will normalize extensive
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values by the number of atoms in the system, depending on the
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“thermo_modify norm” setting. It will not normalize intensive values.
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If a fix value is accessed in another way, e.g. by a
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<a class="reference internal" href="variable.html"><span class="doc">variable</span></a>, you may want to know whether it is an
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intensive or extensive value. See the doc page for individual fixes
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for further info.</p>
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<hr class="docutils" />
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<p>Each fix style has its own documentation page which describes its
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arguments and what it does, as listed below. Here is an alphabetic
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list of fix styles available in LAMMPS. They are also given in more
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compact form in the Fix section of <a class="reference internal" href="Section_commands.html#cmd-5"><span class="std std-ref">this page</span></a>.</p>
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<p>There are also additional fix styles (not listed here) submitted by
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users which are included in the LAMMPS distribution. The list of
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these with links to the individual styles are given in the fix section
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of <a class="reference internal" href="Section_commands.html#cmd-5"><span class="std std-ref">this page</span></a>.</p>
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<ul class="simple">
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<li><a class="reference internal" href="fix_adapt.html"><span class="doc">adapt</span></a> - change a simulation parameter over time</li>
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<li><a class="reference internal" href="fix_addforce.html"><span class="doc">addforce</span></a> - add a force to each atom</li>
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<li><a class="reference internal" href="fix_append_atoms.html"><span class="doc">append/atoms</span></a> - append atoms to a running simulation</li>
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<li><a class="reference internal" href="fix_atom_swap.html"><span class="doc">atom/swap</span></a> - Monte Carlo atom type swapping</li>
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<li><a class="reference internal" href="fix_aveforce.html"><span class="doc">aveforce</span></a> - add an averaged force to each atom</li>
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<li><a class="reference internal" href="fix_ave_atom.html"><span class="doc">ave/atom</span></a> - compute per-atom time-averaged quantities</li>
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<li><a class="reference internal" href="fix_ave_chunk.html"><span class="doc">ave/chunk</span></a> - compute per-chunk time-averaged quantities</li>
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<li><a class="reference internal" href="fix_ave_correlate.html"><span class="doc">ave/correlate</span></a> - compute/output time correlations</li>
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<li><a class="reference internal" href="fix_ave_histo.html"><span class="doc">ave/histo</span></a> - compute/output time-averaged histograms</li>
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<li><a class="reference internal" href="fix_ave_spatial.html"><span class="doc">ave/spatial</span></a> - compute/output time-averaged per-atom quantities by layer</li>
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<li><a class="reference internal" href="fix_ave_time.html"><span class="doc">ave/time</span></a> - compute/output global time-averaged quantities</li>
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<li><a class="reference internal" href="fix_balance.html"><span class="doc">balance</span></a> - perform dynamic load-balancing</li>
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<li><a class="reference internal" href="fix_bond_break.html"><span class="doc">bond/break</span></a> - break bonds on the fly</li>
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<li><a class="reference internal" href="fix_bond_create.html"><span class="doc">bond/create</span></a> - create bonds on the fly</li>
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<li><a class="reference internal" href="fix_bond_swap.html"><span class="doc">bond/swap</span></a> - Monte Carlo bond swapping</li>
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<li><a class="reference internal" href="fix_box_relax.html"><span class="doc">box/relax</span></a> - relax box size during energy minimization</li>
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<li><a class="reference internal" href="fix_deform.html"><span class="doc">deform</span></a> - change the simulation box size/shape</li>
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<li><a class="reference internal" href="fix_deposit.html"><span class="doc">deposit</span></a> - add new atoms above a surface</li>
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<li><a class="reference internal" href="fix_drag.html"><span class="doc">drag</span></a> - drag atoms towards a defined coordinate</li>
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<li><a class="reference internal" href="fix_dt_reset.html"><span class="doc">dt/reset</span></a> - reset the timestep based on velocity, forces</li>
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<li><a class="reference internal" href="fix_efield.html"><span class="doc">efield</span></a> - impose electric field on system</li>
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<li><a class="reference internal" href="fix_enforce2d.html"><span class="doc">enforce2d</span></a> - zero out z-dimension velocity and force</li>
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<li><a class="reference internal" href="fix_evaporate.html"><span class="doc">evaporate</span></a> - remove atoms from simulation periodically</li>
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<li><a class="reference internal" href="fix_external.html"><span class="doc">external</span></a> - callback to an external driver program</li>
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<li><a class="reference internal" href="fix_freeze.html"><span class="doc">freeze</span></a> - freeze atoms in a granular simulation</li>
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<li><a class="reference internal" href="fix_gcmc.html"><span class="doc">gcmc</span></a> - grand canonical insertions/deletions</li>
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<li><a class="reference internal" href="fix_gcmc.html"><span class="doc">gld</span></a> - generalized Langevin dynamics integrator</li>
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<li><a class="reference internal" href="fix_gravity.html"><span class="doc">gravity</span></a> - add gravity to atoms in a granular simulation</li>
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<li><a class="reference internal" href="fix_heat.html"><span class="doc">heat</span></a> - add/subtract momentum-conserving heat</li>
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<li><a class="reference internal" href="fix_indent.html"><span class="doc">indent</span></a> - impose force due to an indenter</li>
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<li><a class="reference internal" href="fix_langevin.html"><span class="doc">langevin</span></a> - Langevin temperature control</li>
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<li><a class="reference internal" href="fix_lineforce.html"><span class="doc">lineforce</span></a> - constrain atoms to move in a line</li>
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<li><a class="reference internal" href="fix_momentum.html"><span class="doc">momentum</span></a> - zero the linear and/or angular momentum of a group of atoms</li>
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<li><a class="reference internal" href="fix_move.html"><span class="doc">move</span></a> - move atoms in a prescribed fashion</li>
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<li><a class="reference internal" href="fix_msst.html"><span class="doc">msst</span></a> - multi-scale shock technique (MSST) integration</li>
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<li><a class="reference internal" href="fix_neb.html"><span class="doc">neb</span></a> - nudged elastic band (NEB) spring forces</li>
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<li><a class="reference internal" href="fix_nh.html"><span class="doc">nph</span></a> - constant NPH time integration via Nose/Hoover</li>
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<li><a class="reference internal" href="fix_nphug.html"><span class="doc">nphug</span></a> - constant-stress Hugoniostat integration</li>
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<li><a class="reference internal" href="fix_nph_asphere.html"><span class="doc">nph/asphere</span></a> - NPH for aspherical particles</li>
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<li><a class="reference internal" href="fix_nve_body.html"><span class="doc">nph/body</span></a> - NPH for body particles</li>
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<li><a class="reference internal" href="fix_nph_sphere.html"><span class="doc">nph/sphere</span></a> - NPH for spherical particles</li>
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<li><a class="reference internal" href="fix_nh.html"><span class="doc">npt</span></a> - constant NPT time integration via Nose/Hoover</li>
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<li><a class="reference internal" href="fix_npt_asphere.html"><span class="doc">npt/asphere</span></a> - NPT for aspherical particles</li>
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<li><a class="reference internal" href="fix_nve_body.html"><span class="doc">npt/body</span></a> - NPT for body particles</li>
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<li><a class="reference internal" href="fix_npt_sphere.html"><span class="doc">npt/sphere</span></a> - NPT for spherical particles</li>
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<li><a class="reference internal" href="fix_nve.html"><span class="doc">nve</span></a> - constant NVE time integration</li>
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<li><a class="reference internal" href="fix_nve_asphere.html"><span class="doc">nve/asphere</span></a> - NVE for aspherical particles</li>
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<li><a class="reference internal" href="fix_nve_asphere_noforce.html"><span class="doc">nve/asphere/noforce</span></a> - NVE for aspherical particles without forces”</li>
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<li><a class="reference internal" href="fix_nve_body.html"><span class="doc">nve/body</span></a> - NVE for body particles</li>
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<li><a class="reference internal" href="fix_nve_limit.html"><span class="doc">nve/limit</span></a> - NVE with limited step length</li>
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<li><a class="reference internal" href="fix_nve_line.html"><span class="doc">nve/line</span></a> - NVE for line segments</li>
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<li><a class="reference internal" href="fix_nve_noforce.html"><span class="doc">nve/noforce</span></a> - NVE without forces (v only)</li>
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<li><a class="reference internal" href="fix_nve_sphere.html"><span class="doc">nve/sphere</span></a> - NVE for spherical particles</li>
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<li><a class="reference internal" href="fix_nve_tri.html"><span class="doc">nve/tri</span></a> - NVE for triangles</li>
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<li><a class="reference internal" href="fix_nh.html"><span class="doc">nvt</span></a> - constant NVT time integration via Nose/Hoover</li>
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<li><a class="reference internal" href="fix_nvt_asphere.html"><span class="doc">nvt/asphere</span></a> - NVT for aspherical particles</li>
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<li><a class="reference internal" href="fix_nve_body.html"><span class="doc">nvt/body</span></a> - NVT for body particles</li>
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<li><a class="reference internal" href="fix_nvt_sllod.html"><span class="doc">nvt/sllod</span></a> - NVT for NEMD with SLLOD equations</li>
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<li><a class="reference internal" href="fix_nvt_sphere.html"><span class="doc">nvt/sphere</span></a> - NVT for spherical particles</li>
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<li><a class="reference internal" href="fix_oneway.html"><span class="doc">oneway</span></a> - constrain particles on move in one direction</li>
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<li><a class="reference internal" href="fix_orient_fcc.html"><span class="doc">orient/fcc</span></a> - add grain boundary migration force</li>
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|
<li><a class="reference internal" href="fix_planeforce.html"><span class="doc">planeforce</span></a> - constrain atoms to move in a plane</li>
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<li><a class="reference internal" href="fix_poems.html"><span class="doc">poems</span></a> - constrain clusters of atoms to move as coupled rigid bodies</li>
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<li><a class="reference internal" href="fix_pour.html"><span class="doc">pour</span></a> - pour new atoms/molecules into a granular simulation domain</li>
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<li><a class="reference internal" href="fix_press_berendsen.html"><span class="doc">press/berendsen</span></a> - pressure control by Berendsen barostat</li>
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<li><a class="reference internal" href="fix_print.html"><span class="doc">print</span></a> - print text and variables during a simulation</li>
|
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<li><a class="reference internal" href="fix_property_atom.html"><span class="doc">property/atom</span></a> - add customized per-atom values</li>
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<li><a class="reference internal" href="fix_qeq_comb.html"><span class="doc">qeq/comb</span></a> - charge equilibration for COMB potential <a class="reference internal" href="fix_qeq.html"><span class="doc">qeq/dynamic</span></a> - charge equilibration via dynamic method <a class="reference internal" href="fix_qeq.html"><span class="doc">qeq/fire</span></a> - charge equilibration via FIRE minimizer <a class="reference internal" href="fix_qeq.html"><span class="doc">qeq/point</span></a> - charge equilibration via point method <a class="reference internal" href="fix_qeq.html"><span class="doc">qeq/shielded</span></a> - charge equilibration via shielded method <a class="reference internal" href="fix_qeq.html"><span class="doc">qeq/slater</span></a> - charge equilibration via Slater method <a class="reference internal" href="fix_shake.html"><span class="doc">rattle</span></a> - RATTLE constraints on bonds and/or angles</li>
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<li><a class="reference internal" href="fix_reax_bonds.html"><span class="doc">reax/bonds</span></a> - write out ReaxFF bond information <a class="reference internal" href="fix_recenter.html"><span class="doc">recenter</span></a> - constrain the center-of-mass position of a group of atoms</li>
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<li><a class="reference internal" href="fix_restrain.html"><span class="doc">restrain</span></a> - constrain a bond, angle, dihedral</li>
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<li><a class="reference internal" href="fix_rigid.html"><span class="doc">rigid</span></a> - constrain one or more clusters of atoms to move as a rigid body with NVE integration</li>
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<li><a class="reference internal" href="fix_rigid.html"><span class="doc">rigid/nph</span></a> - constrain one or more clusters of atoms to move as a rigid body with NPH integration</li>
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<li><a class="reference internal" href="fix_rigid.html"><span class="doc">rigid/npt</span></a> - constrain one or more clusters of atoms to move as a rigid body with NPT integration</li>
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<li><a class="reference internal" href="fix_rigid.html"><span class="doc">rigid/nve</span></a> - constrain one or more clusters of atoms to move as a rigid body with alternate NVE integration</li>
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<li><a class="reference internal" href="fix_rigid.html"><span class="doc">rigid/nvt</span></a> - constrain one or more clusters of atoms to move as a rigid body with NVT integration</li>
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<li><a class="reference internal" href="fix_rigid.html"><span class="doc">rigid/small</span></a> - constrain many small clusters of atoms to move as a rigid body with NVE integration</li>
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|
<li><a class="reference internal" href="fix_rigid.html"><span class="doc">rigid/small/nph</span></a> - constrain many small clusters of atoms to move as a rigid body with NPH integration</li>
|
|
<li><a class="reference internal" href="fix_rigid.html"><span class="doc">rigid/small/npt</span></a> - constrain many small clusters of atoms to move as a rigid body with NPT integration</li>
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|
<li><a class="reference internal" href="fix_rigid.html"><span class="doc">rigid/small/nve</span></a> - constrain many small clusters of atoms to move as a rigid body with alternate NVE integration</li>
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<li><a class="reference internal" href="fix_rigid.html"><span class="doc">rigid/small/nvt</span></a> - constrain many small clusters of atoms to move as a rigid body with NVT integration</li>
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<li><a class="reference internal" href="fix_setforce.html"><span class="doc">setforce</span></a> - set the force on each atom</li>
|
|
<li><a class="reference internal" href="fix_shake.html"><span class="doc">shake</span></a> - SHAKE constraints on bonds and/or angles</li>
|
|
<li><a class="reference internal" href="fix_spring.html"><span class="doc">spring</span></a> - apply harmonic spring force to group of atoms</li>
|
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<li><a class="reference internal" href="fix_spring_rg.html"><span class="doc">spring/rg</span></a> - spring on radius of gyration of group of atoms</li>
|
|
<li><a class="reference internal" href="fix_spring_self.html"><span class="doc">spring/self</span></a> - spring from each atom to its origin</li>
|
|
<li><a class="reference internal" href="fix_srd.html"><span class="doc">srd</span></a> - stochastic rotation dynamics (SRD)</li>
|
|
<li><a class="reference internal" href="fix_store_force.html"><span class="doc">store/force</span></a> - store force on each atom</li>
|
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<li><a class="reference internal" href="fix_store_state.html"><span class="doc">store/state</span></a> - store attributes for each atom</li>
|
|
<li><a class="reference internal" href="fix_temp_berendsen.html"><span class="doc">temp/berendsen</span></a> - temperature control by Berendsen thermostat</li>
|
|
<li><a class="reference internal" href="fix_temp_csvr.html"><span class="doc">temp/csld</span></a> - canonical sampling thermostat with Langevin dynamics</li>
|
|
<li><a class="reference internal" href="fix_temp_csvr.html"><span class="doc">temp/csvr</span></a> - canonical sampling thermostat with Hamiltonian dynamics</li>
|
|
<li><a class="reference internal" href="fix_temp_rescale.html"><span class="doc">temp/rescale</span></a> - temperature control by velocity rescaling</li>
|
|
<li><a class="reference internal" href="fix_tfmc.html"><span class="doc">tfmc</span></a> - perform force-bias Monte Carlo with time-stamped method</li>
|
|
<li><a class="reference internal" href="fix_thermal_conductivity.html"><span class="doc">thermal/conductivity</span></a> - Muller-Plathe kinetic energy exchange for thermal conductivity calculation</li>
|
|
<li><a class="reference internal" href="fix_tmd.html"><span class="doc">tmd</span></a> - guide a group of atoms to a new configuration</li>
|
|
<li><a class="reference internal" href="fix_ttm.html"><span class="doc">ttm</span></a> - two-temperature model for electronic/atomic coupling</li>
|
|
<li><a class="reference internal" href="fix_tune_kspace.html"><span class="doc">tune/kspace</span></a> - auto-tune KSpace parameters</li>
|
|
<li><a class="reference internal" href="fix_vector.html"><span class="doc">vector</span></a> - accumulate a global vector every N timesteps</li>
|
|
<li><a class="reference internal" href="fix_viscosity.html"><span class="doc">viscosity</span></a> - Muller-Plathe momentum exchange for viscosity calculation</li>
|
|
<li><a class="reference internal" href="fix_viscous.html"><span class="doc">viscous</span></a> - viscous damping for granular simulations</li>
|
|
<li><a class="reference internal" href="fix_wall.html"><span class="doc">wall/colloid</span></a> - Lennard-Jones wall interacting with finite-size particles</li>
|
|
<li><a class="reference internal" href="fix_wall_gran.html"><span class="doc">wall/gran</span></a> - frictional wall(s) for granular simulations</li>
|
|
<li><a class="reference internal" href="fix_wall.html"><span class="doc">wall/harmonic</span></a> - harmonic spring wall</li>
|
|
<li><a class="reference internal" href="fix_wall.html"><span class="doc">wall/lj1043</span></a> - Lennard-Jones 10-4-3 wall</li>
|
|
<li><a class="reference internal" href="fix_wall.html"><span class="doc">wall/lj126</span></a> - Lennard-Jones 12-6 wall</li>
|
|
<li><a class="reference internal" href="fix_wall.html"><span class="doc">wall/lj93</span></a> - Lennard-Jones 9-3 wall</li>
|
|
<li><a class="reference internal" href="fix_wall_piston.html"><span class="doc">wall/piston</span></a> - moving reflective piston wall</li>
|
|
<li><a class="reference internal" href="fix_wall_reflect.html"><span class="doc">wall/reflect</span></a> - reflecting wall(s)</li>
|
|
<li><a class="reference internal" href="fix_wall_region.html"><span class="doc">wall/region</span></a> - use region surface as wall</li>
|
|
<li><a class="reference internal" href="fix_wall_srd.html"><span class="doc">wall/srd</span></a> - slip/no-slip wall for SRD particles</li>
|
|
</ul>
|
|
</div>
|
|
<div class="section" id="restrictions">
|
|
<h2>Restrictions</h2>
|
|
<p>Some fix styles are part of specific packages. They are only enabled
|
|
if LAMMPS was built with that package. See the <a class="reference internal" href="Section_start.html#start-3"><span class="std std-ref">Making LAMMPS</span></a> section for more info on packages.
|
|
The doc pages for individual fixes tell if it is part of a package.</p>
|
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</div>
|
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<div class="section" id="related-commands">
|
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<h2>Related commands</h2>
|
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<p><a class="reference internal" href="unfix.html"><span class="doc">unfix</span></a>, <a class="reference internal" href="fix_modify.html"><span class="doc">fix_modify</span></a></p>
|
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<p><strong>Default:</strong> none</p>
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</div>
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</div>
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</div>
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<footer>
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