1018 lines
85 KiB
HTML
1018 lines
85 KiB
HTML
<!DOCTYPE html>
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<html class="writer-html5" lang="en" >
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<head>
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<title>fix wall/lj93 command — LAMMPS documentation</title>
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<link rel="index" title="Index" href="genindex.html" />
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<link rel="search" title="Search" href="search.html" />
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<link rel="next" title="fix wall/body/polygon command" href="fix_wall_body_polygon.html" />
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<div class="wy-grid-for-nav">
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<img src="_static/lammps-logo.png" class="logo" alt="Logo"/>
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<div class="lammps_version">Version: <b>19 Nov 2024</b></div>
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<div class="lammps_release">git info: </div>
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</div><div class="wy-menu wy-menu-vertical" data-spy="affix" role="navigation" aria-label="Navigation menu">
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<p class="caption" role="heading"><span class="caption-text">User Guide</span></p>
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<ul>
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<li class="toctree-l1"><a class="reference internal" href="Intro.html">1. Introduction</a></li>
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<li class="toctree-l1"><a class="reference internal" href="Install.html">2. Install LAMMPS</a></li>
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<li class="toctree-l1"><a class="reference internal" href="Build.html">3. Build LAMMPS</a></li>
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<li class="toctree-l1"><a class="reference internal" href="Run_head.html">4. Run LAMMPS</a></li>
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<li class="toctree-l1"><a class="reference internal" href="Commands.html">5. Commands</a></li>
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<li class="toctree-l1"><a class="reference internal" href="Packages.html">6. Optional packages</a></li>
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<li class="toctree-l1"><a class="reference internal" href="Speed.html">7. Accelerate performance</a></li>
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<li class="toctree-l1"><a class="reference internal" href="Howto.html">8. Howto discussions</a></li>
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<li class="toctree-l1"><a class="reference internal" href="Examples.html">9. Example scripts</a></li>
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<li class="toctree-l1"><a class="reference internal" href="Tools.html">10. Auxiliary tools</a></li>
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<li class="toctree-l1"><a class="reference internal" href="Errors.html">11. Errors</a></li>
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</ul>
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<p class="caption" role="heading"><span class="caption-text">Programmer Guide</span></p>
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<ul>
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<li class="toctree-l1"><a class="reference internal" href="Library.html">1. LAMMPS Library Interfaces</a></li>
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<li class="toctree-l1"><a class="reference internal" href="Python_head.html">2. Use Python with LAMMPS</a></li>
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<li class="toctree-l1"><a class="reference internal" href="Modify.html">3. Modifying & extending LAMMPS</a></li>
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<li class="toctree-l1"><a class="reference internal" href="Developer.html">4. Information for Developers</a></li>
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</ul>
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<p class="caption" role="heading"><span class="caption-text">Command Reference</span></p>
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<ul class="current">
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<li class="toctree-l1"><a class="reference internal" href="commands_list.html">Commands</a></li>
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<li class="toctree-l1 current"><a class="reference internal" href="fixes.html">Fix Styles</a><ul class="current">
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<li class="toctree-l2"><a class="reference internal" href="fix_accelerate_cos.html">fix accelerate/cos command</a></li>
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<li class="toctree-l2"><a class="reference internal" href="fix_acks2_reaxff.html">fix acks2/reaxff command</a></li>
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<li class="toctree-l2"><a class="reference internal" href="fix_adapt.html">fix adapt command</a></li>
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<li class="toctree-l2"><a class="reference internal" href="fix_adapt_fep.html">fix adapt/fep command</a></li>
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<li class="toctree-l2"><a class="reference internal" href="fix_add_heat.html">fix add/heat command</a></li>
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<li class="toctree-l2"><a class="reference internal" href="fix_addforce.html">fix addforce command</a></li>
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<li class="toctree-l2"><a class="reference internal" href="fix_addtorque.html">fix addtorque command</a></li>
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<li class="toctree-l2"><a class="reference internal" href="fix_alchemy.html">fix alchemy command</a></li>
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<li class="toctree-l2"><a class="reference internal" href="fix_amoeba_bitorsion.html">fix amoeba/bitorsion command</a></li>
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<li class="toctree-l2"><a class="reference internal" href="fix_amoeba_pitorsion.html">fix amoeba/pitorsion command</a></li>
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<li class="toctree-l2"><a class="reference internal" href="fix_append_atoms.html">fix append/atoms command</a></li>
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<li class="toctree-l2"><a class="reference internal" href="fix_atc.html">fix atc command</a></li>
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<li class="toctree-l2"><a class="reference internal" href="fix_atom_swap.html">fix atom/swap command</a></li>
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<li class="toctree-l2"><a class="reference internal" href="fix_ave_atom.html">fix ave/atom command</a></li>
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<li class="toctree-l2"><a class="reference internal" href="fix_ave_chunk.html">fix ave/chunk command</a></li>
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<li class="toctree-l2"><a class="reference internal" href="fix_ave_correlate.html">fix ave/correlate command</a></li>
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<li class="toctree-l2"><a class="reference internal" href="fix_ave_correlate_long.html">fix ave/correlate/long command</a></li>
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<li class="toctree-l2"><a class="reference internal" href="fix_ave_grid.html">fix ave/grid command</a></li>
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<li class="toctree-l2"><a class="reference internal" href="fix_ave_histo.html">fix ave/histo command</a></li>
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<li class="toctree-l2"><a class="reference internal" href="fix_ave_histo.html#fix-ave-histo-weight-command">fix ave/histo/weight command</a></li>
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<li class="toctree-l2"><a class="reference internal" href="fix_ave_spatial.html">fix ave/spatial command</a></li>
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<li class="toctree-l2"><a class="reference internal" href="fix_ave_spatial_sphere.html">fix ave/spatial/sphere command</a></li>
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<li class="toctree-l2"><a class="reference internal" href="fix_ave_time.html">fix ave/time command</a></li>
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<li class="toctree-l2"><a class="reference internal" href="fix_aveforce.html">fix aveforce command</a></li>
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<li class="toctree-l2"><a class="reference internal" href="fix_balance.html">fix balance command</a></li>
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<li class="toctree-l2"><a class="reference internal" href="fix_bocs.html">fix bocs command</a></li>
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<li class="toctree-l2"><a class="reference internal" href="fix_bond_break.html">fix bond/break command</a></li>
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<li class="toctree-l2"><a class="reference internal" href="fix_bond_create.html">fix bond/create command</a></li>
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<li class="toctree-l2"><a class="reference internal" href="fix_bond_create.html#fix-bond-create-angle-command">fix bond/create/angle command</a></li>
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<li class="toctree-l2"><a class="reference internal" href="fix_bond_react.html">fix bond/react command</a></li>
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<li class="toctree-l2"><a class="reference internal" href="fix_bond_swap.html">fix bond/swap command</a></li>
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<li class="toctree-l2"><a class="reference internal" href="fix_box_relax.html">fix box/relax command</a></li>
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<li class="toctree-l2"><a class="reference internal" href="fix_brownian.html">fix brownian command</a></li>
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<li class="toctree-l2"><a class="reference internal" href="fix_brownian.html#fix-brownian-sphere-command">fix brownian/sphere command</a></li>
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<li class="toctree-l2"><a class="reference internal" href="fix_brownian.html#fix-brownian-asphere-command">fix brownian/asphere command</a></li>
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<li class="toctree-l2"><a class="reference internal" href="fix_charge_regulation.html">fix charge/regulation command</a></li>
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<li class="toctree-l2"><a class="reference internal" href="fix_cmap.html">fix cmap command</a></li>
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<li class="toctree-l2"><a class="reference internal" href="fix_colvars.html">fix colvars command</a></li>
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<li class="toctree-l2"><a class="reference internal" href="fix_controller.html">fix controller command</a></li>
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<li class="toctree-l2"><a class="reference internal" href="fix_damping_cundall.html">fix damping/cundall command</a></li>
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<li class="toctree-l2"><a class="reference internal" href="fix_deform.html">fix deform command</a></li>
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<li class="toctree-l2"><a class="reference internal" href="fix_deform_pressure.html">fix deform/pressure command</a></li>
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<li class="toctree-l2"><a class="reference internal" href="fix_deposit.html">fix deposit command</a></li>
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<li class="toctree-l2"><a class="reference internal" href="fix_dpd_energy.html">fix dpd/energy command</a></li>
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||
<li class="toctree-l2"><a class="reference internal" href="fix_dpd_source.html">fix edpd/source command</a></li>
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||
<li class="toctree-l2"><a class="reference internal" href="fix_dpd_source.html#fix-tdpd-source-command">fix tdpd/source command</a></li>
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<li class="toctree-l2"><a class="reference internal" href="fix_drag.html">fix drag command</a></li>
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||
<li class="toctree-l2"><a class="reference internal" href="fix_drude.html">fix drude command</a></li>
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||
<li class="toctree-l2"><a class="reference internal" href="fix_drude_transform.html">fix drude/transform/direct command</a></li>
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<li class="toctree-l2"><a class="reference internal" href="fix_drude_transform.html#fix-drude-transform-inverse-command">fix drude/transform/inverse command</a></li>
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<li class="toctree-l2"><a class="reference internal" href="fix_dt_reset.html">fix dt/reset command</a></li>
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<li class="toctree-l2"><a class="reference internal" href="fix_efield.html">fix efield command</a></li>
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<li class="toctree-l2"><a class="reference internal" href="fix_efield.html#fix-efield-tip4p-command">fix efield/tip4p command</a></li>
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<li class="toctree-l2"><a class="reference internal" href="fix_ehex.html">fix ehex command</a></li>
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<li class="toctree-l2"><a class="reference internal" href="fix_electrode.html">fix electrode/conp command</a></li>
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<li class="toctree-l2"><a class="reference internal" href="fix_electrode.html#fix-electrode-conq-command">fix electrode/conq command</a></li>
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<li class="toctree-l2"><a class="reference internal" href="fix_electrode.html#fix-electrode-thermo-command">fix electrode/thermo command</a></li>
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<li class="toctree-l2"><a class="reference internal" href="fix_electron_stopping.html">fix electron/stopping command</a></li>
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<li class="toctree-l2"><a class="reference internal" href="fix_electron_stopping.html#fix-electron-stopping-fit-command">fix electron/stopping/fit command</a></li>
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||
<li class="toctree-l2"><a class="reference internal" href="fix_enforce2d.html">fix enforce2d command</a></li>
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||
<li class="toctree-l2"><a class="reference internal" href="fix_eos_cv.html">fix eos/cv command</a></li>
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||
<li class="toctree-l2"><a class="reference internal" href="fix_eos_table.html">fix eos/table command</a></li>
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||
<li class="toctree-l2"><a class="reference internal" href="fix_eos_table_rx.html">fix eos/table/rx command</a></li>
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||
<li class="toctree-l2"><a class="reference internal" href="fix_evaporate.html">fix evaporate command</a></li>
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||
<li class="toctree-l2"><a class="reference internal" href="fix_external.html">fix external command</a></li>
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<li class="toctree-l2"><a class="reference internal" href="fix_ffl.html">fix ffl command</a></li>
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<li class="toctree-l2"><a class="reference internal" href="fix_filter_corotate.html">fix filter/corotate command</a></li>
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<li class="toctree-l2"><a class="reference internal" href="fix_flow_gauss.html">fix flow/gauss command</a></li>
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||
<li class="toctree-l2"><a class="reference internal" href="fix_freeze.html">fix freeze command</a></li>
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<li class="toctree-l2"><a class="reference internal" href="fix_gcmc.html">fix gcmc command</a></li>
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<li class="toctree-l2"><a class="reference internal" href="fix_gld.html">fix gld command</a></li>
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<li class="toctree-l2"><a class="reference internal" href="fix_gle.html">fix gle command</a></li>
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<li class="toctree-l2"><a class="reference internal" href="fix_gravity.html">fix gravity command</a></li>
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<li class="toctree-l2"><a class="reference internal" href="fix_grem.html">fix grem command</a></li>
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<li class="toctree-l2"><a class="reference internal" href="fix_halt.html">fix halt command</a></li>
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<li class="toctree-l2"><a class="reference internal" href="fix_heat.html">fix heat command</a></li>
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<li class="toctree-l2"><a class="reference internal" href="fix_heat_flow.html">fix heat/flow command</a></li>
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<li class="toctree-l2"><a class="reference internal" href="fix_hyper_global.html">fix hyper/global command</a></li>
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<li class="toctree-l2"><a class="reference internal" href="fix_hyper_local.html">fix hyper/local command</a></li>
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<li class="toctree-l2"><a class="reference internal" href="fix_imd.html">fix imd command</a></li>
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||
<li class="toctree-l2"><a class="reference internal" href="fix_indent.html">fix indent command</a></li>
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<li class="toctree-l2"><a class="reference internal" href="fix_ipi.html">fix ipi command</a></li>
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<li class="toctree-l2"><a class="reference internal" href="fix_langevin.html">fix langevin command</a></li>
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<li class="toctree-l2"><a class="reference internal" href="fix_langevin_drude.html">fix langevin/drude command</a></li>
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<li class="toctree-l2"><a class="reference internal" href="fix_langevin_eff.html">fix langevin/eff command</a></li>
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<li class="toctree-l2"><a class="reference internal" href="fix_langevin_spin.html">fix langevin/spin command</a></li>
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<li class="toctree-l2"><a class="reference internal" href="fix_lb_fluid.html">fix lb/fluid command</a></li>
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<li class="toctree-l2"><a class="reference internal" href="fix_lb_momentum.html">fix lb/momentum command</a></li>
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<li class="toctree-l2"><a class="reference internal" href="fix_lb_viscous.html">fix lb/viscous command</a></li>
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<li class="toctree-l2"><a class="reference internal" href="fix_lineforce.html">fix lineforce command</a></li>
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<li class="toctree-l2"><a class="reference internal" href="fix_manifoldforce.html">fix manifoldforce command</a></li>
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||
<li class="toctree-l2"><a class="reference internal" href="fix_mdi_qm.html">fix mdi/qm command</a></li>
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||
<li class="toctree-l2"><a class="reference internal" href="fix_mdi_qmmm.html">fix mdi/qmmm command</a></li>
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<li class="toctree-l2"><a class="reference internal" href="fix_meso_move.html">fix meso/move command</a></li>
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<li class="toctree-l2"><a class="reference internal" href="fix_mol_swap.html">fix mol/swap command</a></li>
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<li class="toctree-l2"><a class="reference internal" href="fix_momentum.html">fix momentum command</a></li>
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<li class="toctree-l2"><a class="reference internal" href="fix_momentum.html#fix-momentum-chunk-command">fix momentum/chunk command</a></li>
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||
<li class="toctree-l2"><a class="reference internal" href="fix_move.html">fix move command</a></li>
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<li class="toctree-l2"><a class="reference internal" href="fix_msst.html">fix msst command</a></li>
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<li class="toctree-l2"><a class="reference internal" href="fix_mvv_dpd.html">fix mvv/dpd command</a></li>
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<li class="toctree-l2"><a class="reference internal" href="fix_mvv_dpd.html#fix-mvv-edpd-command">fix mvv/edpd command</a></li>
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<li class="toctree-l2"><a class="reference internal" href="fix_mvv_dpd.html#fix-mvv-tdpd-command">fix mvv/tdpd command</a></li>
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||
<li class="toctree-l2"><a class="reference internal" href="fix_neb.html">fix neb command</a></li>
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<li class="toctree-l2"><a class="reference internal" href="fix_neb_spin.html">fix neb/spin command</a></li>
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||
<li class="toctree-l2"><a class="reference internal" href="fix_nh.html">fix nvt command</a></li>
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<li class="toctree-l2"><a class="reference internal" href="fix_nh.html#fix-npt-command">fix npt command</a></li>
|
||
<li class="toctree-l2"><a class="reference internal" href="fix_nh.html#fix-nph-command">fix nph command</a></li>
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<li class="toctree-l2"><a class="reference internal" href="fix_nh_eff.html">fix nvt/eff command</a></li>
|
||
<li class="toctree-l2"><a class="reference internal" href="fix_nh_eff.html#fix-npt-eff-command">fix npt/eff command</a></li>
|
||
<li class="toctree-l2"><a class="reference internal" href="fix_nh_eff.html#fix-nph-eff-command">fix nph/eff command</a></li>
|
||
<li class="toctree-l2"><a class="reference internal" href="fix_nh_uef.html">fix nvt/uef command</a></li>
|
||
<li class="toctree-l2"><a class="reference internal" href="fix_nh_uef.html#fix-npt-uef-command">fix npt/uef command</a></li>
|
||
<li class="toctree-l2"><a class="reference internal" href="fix_nonaffine_displacement.html">fix nonaffine/displacement command</a></li>
|
||
<li class="toctree-l2"><a class="reference internal" href="fix_nph_asphere.html">fix nph/asphere command</a></li>
|
||
<li class="toctree-l2"><a class="reference internal" href="fix_nph_body.html">fix nph/body command</a></li>
|
||
<li class="toctree-l2"><a class="reference internal" href="fix_nph_sphere.html">fix nph/sphere command</a></li>
|
||
<li class="toctree-l2"><a class="reference internal" href="fix_nphug.html">fix nphug command</a></li>
|
||
<li class="toctree-l2"><a class="reference internal" href="fix_npt_asphere.html">fix npt/asphere command</a></li>
|
||
<li class="toctree-l2"><a class="reference internal" href="fix_npt_body.html">fix npt/body command</a></li>
|
||
<li class="toctree-l2"><a class="reference internal" href="fix_npt_cauchy.html">fix npt/cauchy command</a></li>
|
||
<li class="toctree-l2"><a class="reference internal" href="fix_npt_sphere.html">fix npt/sphere command</a></li>
|
||
<li class="toctree-l2"><a class="reference internal" href="fix_numdiff.html">fix numdiff command</a></li>
|
||
<li class="toctree-l2"><a class="reference internal" href="fix_numdiff_virial.html">fix numdiff/virial command</a></li>
|
||
<li class="toctree-l2"><a class="reference internal" href="fix_nve.html">fix nve command</a></li>
|
||
<li class="toctree-l2"><a class="reference internal" href="fix_nve_asphere.html">fix nve/asphere command</a></li>
|
||
<li class="toctree-l2"><a class="reference internal" href="fix_nve_asphere_noforce.html">fix nve/asphere/noforce command</a></li>
|
||
<li class="toctree-l2"><a class="reference internal" href="fix_nve_awpmd.html">fix nve/awpmd command</a></li>
|
||
<li class="toctree-l2"><a class="reference internal" href="fix_nve_body.html">fix nve/body command</a></li>
|
||
<li class="toctree-l2"><a class="reference internal" href="fix_nve_bpm_sphere.html">fix nve/bpm/sphere command</a></li>
|
||
<li class="toctree-l2"><a class="reference internal" href="fix_nve_dot.html">fix nve/dot command</a></li>
|
||
<li class="toctree-l2"><a class="reference internal" href="fix_nve_dotc_langevin.html">fix nve/dotc/langevin command</a></li>
|
||
<li class="toctree-l2"><a class="reference internal" href="fix_nve_eff.html">fix nve/eff command</a></li>
|
||
<li class="toctree-l2"><a class="reference internal" href="fix_nve_limit.html">fix nve/limit command</a></li>
|
||
<li class="toctree-l2"><a class="reference internal" href="fix_nve_line.html">fix nve/line command</a></li>
|
||
<li class="toctree-l2"><a class="reference internal" href="fix_nve_manifold_rattle.html">fix nve/manifold/rattle command</a></li>
|
||
<li class="toctree-l2"><a class="reference internal" href="fix_nve_noforce.html">fix nve/noforce command</a></li>
|
||
<li class="toctree-l2"><a class="reference internal" href="fix_nve_sphere.html">fix nve/sphere command</a></li>
|
||
<li class="toctree-l2"><a class="reference internal" href="fix_nve_spin.html">fix nve/spin command</a></li>
|
||
<li class="toctree-l2"><a class="reference internal" href="fix_nve_tri.html">fix nve/tri command</a></li>
|
||
<li class="toctree-l2"><a class="reference internal" href="fix_nvk.html">fix nvk command</a></li>
|
||
<li class="toctree-l2"><a class="reference internal" href="fix_nvt_asphere.html">fix nvt/asphere command</a></li>
|
||
<li class="toctree-l2"><a class="reference internal" href="fix_nvt_body.html">fix nvt/body command</a></li>
|
||
<li class="toctree-l2"><a class="reference internal" href="fix_nvt_manifold_rattle.html">fix nvt/manifold/rattle command</a></li>
|
||
<li class="toctree-l2"><a class="reference internal" href="fix_nvt_sllod.html">fix nvt/sllod command</a></li>
|
||
<li class="toctree-l2"><a class="reference internal" href="fix_nvt_sllod_eff.html">fix nvt/sllod/eff command</a></li>
|
||
<li class="toctree-l2"><a class="reference internal" href="fix_nvt_sphere.html">fix nvt/sphere command</a></li>
|
||
<li class="toctree-l2"><a class="reference internal" href="fix_oneway.html">fix oneway command</a></li>
|
||
<li class="toctree-l2"><a class="reference internal" href="fix_orient.html">fix orient/fcc command</a></li>
|
||
<li class="toctree-l2"><a class="reference internal" href="fix_orient.html#fix-orient-bcc-command">fix orient/bcc command</a></li>
|
||
<li class="toctree-l2"><a class="reference internal" href="fix_orient_eco.html">fix orient/eco command</a></li>
|
||
<li class="toctree-l2"><a class="reference internal" href="fix_pafi.html">fix pafi command</a></li>
|
||
<li class="toctree-l2"><a class="reference internal" href="fix_pair.html">fix pair command</a></li>
|
||
<li class="toctree-l2"><a class="reference internal" href="fix_phonon.html">fix phonon command</a></li>
|
||
<li class="toctree-l2"><a class="reference internal" href="fix_pimd.html">fix pimd/langevin command</a></li>
|
||
<li class="toctree-l2"><a class="reference internal" href="fix_pimd.html#fix-pimd-nvt-command">fix pimd/nvt command</a></li>
|
||
<li class="toctree-l2"><a class="reference internal" href="fix_pimdb.html">fix pimdb/langevin command</a></li>
|
||
<li class="toctree-l2"><a class="reference internal" href="fix_pimdb.html#fix-pimdb-nvt-command">fix pimdb/nvt command</a></li>
|
||
<li class="toctree-l2"><a class="reference internal" href="fix_planeforce.html">fix planeforce command</a></li>
|
||
<li class="toctree-l2"><a class="reference internal" href="fix_plumed.html">fix plumed command</a></li>
|
||
<li class="toctree-l2"><a class="reference internal" href="fix_poems.html">fix poems command</a></li>
|
||
<li class="toctree-l2"><a class="reference internal" href="fix_polarize.html">fix polarize/bem/gmres command</a></li>
|
||
<li class="toctree-l2"><a class="reference internal" href="fix_polarize.html#fix-polarize-bem-icc-command">fix polarize/bem/icc command</a></li>
|
||
<li class="toctree-l2"><a class="reference internal" href="fix_polarize.html#fix-polarize-functional-command">fix polarize/functional command</a></li>
|
||
<li class="toctree-l2"><a class="reference internal" href="fix_pour.html">fix pour command</a></li>
|
||
<li class="toctree-l2"><a class="reference internal" href="fix_precession_spin.html">fix precession/spin command</a></li>
|
||
<li class="toctree-l2"><a class="reference internal" href="fix_press_berendsen.html">fix press/berendsen command</a></li>
|
||
<li class="toctree-l2"><a class="reference internal" href="fix_press_langevin.html">fix press/langevin command</a></li>
|
||
<li class="toctree-l2"><a class="reference internal" href="fix_print.html">fix print command</a></li>
|
||
<li class="toctree-l2"><a class="reference internal" href="fix_propel_self.html">fix propel/self command</a></li>
|
||
<li class="toctree-l2"><a class="reference internal" href="fix_property_atom.html">fix property/atom command</a></li>
|
||
<li class="toctree-l2"><a class="reference internal" href="fix_python_invoke.html">fix python/invoke command</a></li>
|
||
<li class="toctree-l2"><a class="reference internal" href="fix_python_move.html">fix python/move command</a></li>
|
||
<li class="toctree-l2"><a class="reference internal" href="fix_qbmsst.html">fix qbmsst command</a></li>
|
||
<li class="toctree-l2"><a class="reference internal" href="fix_qeq.html">fix qeq/point command</a></li>
|
||
<li class="toctree-l2"><a class="reference internal" href="fix_qeq.html#fix-qeq-shielded-command">fix qeq/shielded command</a></li>
|
||
<li class="toctree-l2"><a class="reference internal" href="fix_qeq.html#fix-qeq-slater-command">fix qeq/slater command</a></li>
|
||
<li class="toctree-l2"><a class="reference internal" href="fix_qeq.html#fix-qeq-ctip-command">fix qeq/ctip command</a></li>
|
||
<li class="toctree-l2"><a class="reference internal" href="fix_qeq.html#fix-qeq-dynamic-command">fix qeq/dynamic command</a></li>
|
||
<li class="toctree-l2"><a class="reference internal" href="fix_qeq.html#fix-qeq-fire-command">fix qeq/fire command</a></li>
|
||
<li class="toctree-l2"><a class="reference internal" href="fix_qeq_comb.html">fix qeq/comb command</a></li>
|
||
<li class="toctree-l2"><a class="reference internal" href="fix_qeq_reaxff.html">fix qeq/reaxff command</a></li>
|
||
<li class="toctree-l2"><a class="reference internal" href="fix_qmmm.html">fix qmmm command</a></li>
|
||
<li class="toctree-l2"><a class="reference internal" href="fix_qtb.html">fix qtb command</a></li>
|
||
<li class="toctree-l2"><a class="reference internal" href="fix_qtpie_reaxff.html">fix qtpie/reaxff command</a></li>
|
||
<li class="toctree-l2"><a class="reference internal" href="fix_reaxff_bonds.html">fix reaxff/bonds command</a></li>
|
||
<li class="toctree-l2"><a class="reference internal" href="fix_reaxff_species.html">fix reaxff/species command</a></li>
|
||
<li class="toctree-l2"><a class="reference internal" href="fix_recenter.html">fix recenter command</a></li>
|
||
<li class="toctree-l2"><a class="reference internal" href="fix_restrain.html">fix restrain command</a></li>
|
||
<li class="toctree-l2"><a class="reference internal" href="fix_rheo.html">fix rheo command</a></li>
|
||
<li class="toctree-l2"><a class="reference internal" href="fix_rheo_oxidation.html">fix rheo/oxidation command</a></li>
|
||
<li class="toctree-l2"><a class="reference internal" href="fix_rheo_pressure.html">fix rheo/pressure command</a></li>
|
||
<li class="toctree-l2"><a class="reference internal" href="fix_rheo_thermal.html">fix rheo/thermal command</a></li>
|
||
<li class="toctree-l2"><a class="reference internal" href="fix_rheo_viscosity.html">fix rheo/viscosity command</a></li>
|
||
<li class="toctree-l2"><a class="reference internal" href="fix_rhok.html">fix rhok command</a></li>
|
||
<li class="toctree-l2"><a class="reference internal" href="fix_rigid.html">fix rigid command</a></li>
|
||
<li class="toctree-l2"><a class="reference internal" href="fix_rigid.html#fix-rigid-nve-command">fix rigid/nve command</a></li>
|
||
<li class="toctree-l2"><a class="reference internal" href="fix_rigid.html#fix-rigid-nvt-command">fix rigid/nvt command</a></li>
|
||
<li class="toctree-l2"><a class="reference internal" href="fix_rigid.html#fix-rigid-npt-command">fix rigid/npt command</a></li>
|
||
<li class="toctree-l2"><a class="reference internal" href="fix_rigid.html#fix-rigid-nph-command">fix rigid/nph command</a></li>
|
||
<li class="toctree-l2"><a class="reference internal" href="fix_rigid.html#fix-rigid-small-command">fix rigid/small command</a></li>
|
||
<li class="toctree-l2"><a class="reference internal" href="fix_rigid.html#fix-rigid-nve-small-command">fix rigid/nve/small command</a></li>
|
||
<li class="toctree-l2"><a class="reference internal" href="fix_rigid.html#fix-rigid-nvt-small-command">fix rigid/nvt/small command</a></li>
|
||
<li class="toctree-l2"><a class="reference internal" href="fix_rigid.html#fix-rigid-npt-small-command">fix rigid/npt/small command</a></li>
|
||
<li class="toctree-l2"><a class="reference internal" href="fix_rigid.html#fix-rigid-nph-small-command">fix rigid/nph/small command</a></li>
|
||
<li class="toctree-l2"><a class="reference internal" href="fix_rigid_meso.html">fix rigid/meso command</a></li>
|
||
<li class="toctree-l2"><a class="reference internal" href="fix_rx.html">fix rx command</a></li>
|
||
<li class="toctree-l2"><a class="reference internal" href="fix_saed_vtk.html">fix saed/vtk command</a></li>
|
||
<li class="toctree-l2"><a class="reference internal" href="fix_setforce.html">fix setforce command</a></li>
|
||
<li class="toctree-l2"><a class="reference internal" href="fix_setforce.html#fix-setforce-spin-command">fix setforce/spin command</a></li>
|
||
<li class="toctree-l2"><a class="reference internal" href="fix_sgcmc.html">fix sgcmc command</a></li>
|
||
<li class="toctree-l2"><a class="reference internal" href="fix_shake.html">fix shake command</a></li>
|
||
<li class="toctree-l2"><a class="reference internal" href="fix_shake.html#fix-rattle-command">fix rattle command</a></li>
|
||
<li class="toctree-l2"><a class="reference internal" href="fix_shardlow.html">fix shardlow command</a></li>
|
||
<li class="toctree-l2"><a class="reference internal" href="fix_smd.html">fix smd command</a></li>
|
||
<li class="toctree-l2"><a class="reference internal" href="fix_smd_adjust_dt.html">fix smd/adjust_dt command</a></li>
|
||
<li class="toctree-l2"><a class="reference internal" href="fix_smd_integrate_tlsph.html">fix smd/integrate_tlsph command</a></li>
|
||
<li class="toctree-l2"><a class="reference internal" href="fix_smd_integrate_ulsph.html">fix smd/integrate_ulsph command</a></li>
|
||
<li class="toctree-l2"><a class="reference internal" href="fix_smd_move_triangulated_surface.html">fix smd/move_tri_surf command</a></li>
|
||
<li class="toctree-l2"><a class="reference internal" href="fix_smd_setvel.html">fix smd/setvel command</a></li>
|
||
<li class="toctree-l2"><a class="reference internal" href="fix_smd_wall_surface.html">fix smd/wall_surface command</a></li>
|
||
<li class="toctree-l2"><a class="reference internal" href="fix_sph.html">fix sph command</a></li>
|
||
<li class="toctree-l2"><a class="reference internal" href="fix_sph_stationary.html">fix sph/stationary command</a></li>
|
||
<li class="toctree-l2"><a class="reference internal" href="fix_spring.html">fix spring command</a></li>
|
||
<li class="toctree-l2"><a class="reference internal" href="fix_spring_chunk.html">fix spring/chunk command</a></li>
|
||
<li class="toctree-l2"><a class="reference internal" href="fix_spring_rg.html">fix spring/rg command</a></li>
|
||
<li class="toctree-l2"><a class="reference internal" href="fix_spring_self.html">fix spring/self command</a></li>
|
||
<li class="toctree-l2"><a class="reference internal" href="fix_srd.html">fix srd command</a></li>
|
||
<li class="toctree-l2"><a class="reference internal" href="fix_store_force.html">fix store/force command</a></li>
|
||
<li class="toctree-l2"><a class="reference internal" href="fix_store_state.html">fix store/state command</a></li>
|
||
<li class="toctree-l2"><a class="reference internal" href="fix_temp_berendsen.html">fix temp/berendsen command</a></li>
|
||
<li class="toctree-l2"><a class="reference internal" href="fix_temp_csvr.html">fix temp/csvr command</a></li>
|
||
<li class="toctree-l2"><a class="reference internal" href="fix_temp_csvr.html#fix-temp-csld-command">fix temp/csld command</a></li>
|
||
<li class="toctree-l2"><a class="reference internal" href="fix_temp_rescale.html">fix temp/rescale command</a></li>
|
||
<li class="toctree-l2"><a class="reference internal" href="fix_temp_rescale_eff.html">fix temp/rescale/eff command</a></li>
|
||
<li class="toctree-l2"><a class="reference internal" href="fix_tfmc.html">fix tfmc command</a></li>
|
||
<li class="toctree-l2"><a class="reference internal" href="fix_tgnh_drude.html">fix tgnvt/drude command</a></li>
|
||
<li class="toctree-l2"><a class="reference internal" href="fix_tgnh_drude.html#fix-tgnpt-drude-command">fix tgnpt/drude command</a></li>
|
||
<li class="toctree-l2"><a class="reference internal" href="fix_thermal_conductivity.html">fix thermal/conductivity command</a></li>
|
||
<li class="toctree-l2"><a class="reference internal" href="fix_ti_spring.html">fix ti/spring command</a></li>
|
||
<li class="toctree-l2"><a class="reference internal" href="fix_tmd.html">fix tmd command</a></li>
|
||
<li class="toctree-l2"><a class="reference internal" href="fix_ttm.html">fix ttm command</a></li>
|
||
<li class="toctree-l2"><a class="reference internal" href="fix_ttm.html#fix-ttm-grid-command">fix ttm/grid command</a></li>
|
||
<li class="toctree-l2"><a class="reference internal" href="fix_ttm.html#fix-ttm-mod-command">fix ttm/mod command</a></li>
|
||
<li class="toctree-l2"><a class="reference internal" href="fix_tune_kspace.html">fix tune/kspace command</a></li>
|
||
<li class="toctree-l2"><a class="reference internal" href="fix_vector.html">fix vector command</a></li>
|
||
<li class="toctree-l2"><a class="reference internal" href="fix_viscosity.html">fix viscosity command</a></li>
|
||
<li class="toctree-l2"><a class="reference internal" href="fix_viscous.html">fix viscous command</a></li>
|
||
<li class="toctree-l2"><a class="reference internal" href="fix_viscous_sphere.html">fix viscous/sphere command</a></li>
|
||
<li class="toctree-l2 current"><a class="current reference internal" href="#">fix wall/lj93 command</a></li>
|
||
<li class="toctree-l2"><a class="reference internal" href="#fix-wall-lj126-command">fix wall/lj126 command</a></li>
|
||
<li class="toctree-l2"><a class="reference internal" href="#fix-wall-lj1043-command">fix wall/lj1043 command</a></li>
|
||
<li class="toctree-l2"><a class="reference internal" href="#fix-wall-colloid-command">fix wall/colloid command</a></li>
|
||
<li class="toctree-l2"><a class="reference internal" href="#fix-wall-harmonic-command">fix wall/harmonic command</a></li>
|
||
<li class="toctree-l2"><a class="reference internal" href="#fix-wall-lepton-command">fix wall/lepton command</a></li>
|
||
<li class="toctree-l2"><a class="reference internal" href="#fix-wall-morse-command">fix wall/morse command</a></li>
|
||
<li class="toctree-l2"><a class="reference internal" href="#fix-wall-table-command">fix wall/table command</a><ul>
|
||
<li class="toctree-l3"><a class="reference internal" href="#syntax">Syntax</a></li>
|
||
<li class="toctree-l3"><a class="reference internal" href="#examples">Examples</a></li>
|
||
<li class="toctree-l3"><a class="reference internal" href="#description">Description</a></li>
|
||
<li class="toctree-l3"><a class="reference internal" href="#lepton-expression-syntax-and-features">Lepton expression syntax and features</a></li>
|
||
<li class="toctree-l3"><a class="reference internal" href="#table-file-format">Table file format</a></li>
|
||
<li class="toctree-l3"><a class="reference internal" href="#restart-fix-modify-output-run-start-stop-minimize-info">Restart, fix_modify, output, run start/stop, minimize info</a></li>
|
||
<li class="toctree-l3"><a class="reference internal" href="#restrictions">Restrictions</a></li>
|
||
<li class="toctree-l3"><a class="reference internal" href="#related-commands">Related commands</a></li>
|
||
<li class="toctree-l3"><a class="reference internal" href="#default">Default</a></li>
|
||
</ul>
|
||
</li>
|
||
<li class="toctree-l2"><a class="reference internal" href="fix_wall_body_polygon.html">fix wall/body/polygon command</a></li>
|
||
<li class="toctree-l2"><a class="reference internal" href="fix_wall_body_polyhedron.html">fix wall/body/polyhedron command</a></li>
|
||
<li class="toctree-l2"><a class="reference internal" href="fix_wall_ees.html">fix wall/ees command</a></li>
|
||
<li class="toctree-l2"><a class="reference internal" href="fix_wall_ees.html#fix-wall-region-ees-command">fix wall/region/ees command</a></li>
|
||
<li class="toctree-l2"><a class="reference internal" href="fix_wall_flow.html">fix wall/flow command</a></li>
|
||
<li class="toctree-l2"><a class="reference internal" href="fix_wall_gran.html">fix wall/gran command</a></li>
|
||
<li class="toctree-l2"><a class="reference internal" href="fix_wall_gran_region.html">fix wall/gran/region command</a></li>
|
||
<li class="toctree-l2"><a class="reference internal" href="fix_wall_piston.html">fix wall/piston command</a></li>
|
||
<li class="toctree-l2"><a class="reference internal" href="fix_wall_reflect.html">fix wall/reflect command</a></li>
|
||
<li class="toctree-l2"><a class="reference internal" href="fix_wall_reflect_stochastic.html">fix wall/reflect/stochastic command</a></li>
|
||
<li class="toctree-l2"><a class="reference internal" href="fix_wall_region.html">fix wall/region command</a></li>
|
||
<li class="toctree-l2"><a class="reference internal" href="fix_wall_srd.html">fix wall/srd command</a></li>
|
||
<li class="toctree-l2"><a class="reference internal" href="fix_widom.html">fix widom command</a></li>
|
||
</ul>
|
||
</li>
|
||
<li class="toctree-l1"><a class="reference internal" href="computes.html">Compute Styles</a></li>
|
||
<li class="toctree-l1"><a class="reference internal" href="pairs.html">Pair Styles</a></li>
|
||
<li class="toctree-l1"><a class="reference internal" href="bonds.html">Bond Styles</a></li>
|
||
<li class="toctree-l1"><a class="reference internal" href="angles.html">Angle Styles</a></li>
|
||
<li class="toctree-l1"><a class="reference internal" href="dihedrals.html">Dihedral Styles</a></li>
|
||
<li class="toctree-l1"><a class="reference internal" href="impropers.html">Improper Styles</a></li>
|
||
<li class="toctree-l1"><a class="reference internal" href="dumps.html">Dump Styles</a></li>
|
||
<li class="toctree-l1"><a class="reference internal" href="fix_modify_atc_commands.html">fix_modify AtC commands</a></li>
|
||
<li class="toctree-l1"><a class="reference internal" href="Bibliography.html">Bibliography</a></li>
|
||
</ul>
|
||
|
||
</div>
|
||
</div>
|
||
</nav>
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<div role="navigation" aria-label="Page navigation">
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<ul class="wy-breadcrumbs">
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<li><a href="Manual.html" class="icon icon-home" aria-label="Home"></a></li>
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<li class="breadcrumb-item"><a href="fixes.html">Fix Styles</a></li>
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<li class="breadcrumb-item active">fix wall/lj93 command</li>
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<li class="wy-breadcrumbs-aside">
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<a href="https://www.lammps.org"><img src="_static/lammps-logo.png" width="64" height="16" alt="LAMMPS Homepage"></a> | <a href="Commands_all.html">Commands</a>
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</li>
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</ul><div class="rst-breadcrumbs-buttons" role="navigation" aria-label="Sequential page navigation">
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|
||
<a href="fix_wall_body_polygon.html" class="btn btn-neutral float-right" title="fix wall/body/polygon command" accesskey="n">Next <span class="fa fa-arrow-circle-right" aria-hidden="true"></span></a>
|
||
</div>
|
||
<hr/>
|
||
</div>
|
||
<div role="main" class="document" itemscope="itemscope" itemtype="http://schema.org/Article">
|
||
<div itemprop="articleBody">
|
||
|
||
<p><span class="math notranslate nohighlight">\(\renewcommand{\AA}{\text{Å}}\)</span></p>
|
||
<section id="fix-wall-lj93-command">
|
||
<span id="index-8"></span><span id="index-7"></span><span id="index-6"></span><span id="index-5"></span><span id="index-4"></span><span id="index-3"></span><span id="index-2"></span><span id="index-1"></span><span id="index-0"></span><h1>fix wall/lj93 command<a class="headerlink" href="#fix-wall-lj93-command" title="Link to this heading"></a></h1>
|
||
<p>Accelerator Variants: <em>wall/lj93/kk</em></p>
|
||
</section>
|
||
<section id="fix-wall-lj126-command">
|
||
<h1>fix wall/lj126 command<a class="headerlink" href="#fix-wall-lj126-command" title="Link to this heading"></a></h1>
|
||
</section>
|
||
<section id="fix-wall-lj1043-command">
|
||
<h1>fix wall/lj1043 command<a class="headerlink" href="#fix-wall-lj1043-command" title="Link to this heading"></a></h1>
|
||
</section>
|
||
<section id="fix-wall-colloid-command">
|
||
<h1>fix wall/colloid command<a class="headerlink" href="#fix-wall-colloid-command" title="Link to this heading"></a></h1>
|
||
</section>
|
||
<section id="fix-wall-harmonic-command">
|
||
<h1>fix wall/harmonic command<a class="headerlink" href="#fix-wall-harmonic-command" title="Link to this heading"></a></h1>
|
||
</section>
|
||
<section id="fix-wall-lepton-command">
|
||
<h1>fix wall/lepton command<a class="headerlink" href="#fix-wall-lepton-command" title="Link to this heading"></a></h1>
|
||
</section>
|
||
<section id="fix-wall-morse-command">
|
||
<h1>fix wall/morse command<a class="headerlink" href="#fix-wall-morse-command" title="Link to this heading"></a></h1>
|
||
</section>
|
||
<section id="fix-wall-table-command">
|
||
<h1>fix wall/table command<a class="headerlink" href="#fix-wall-table-command" title="Link to this heading"></a></h1>
|
||
<section id="syntax">
|
||
<h2>Syntax<a class="headerlink" href="#syntax" title="Link to this heading"></a></h2>
|
||
<div class="highlight-LAMMPS notranslate"><div class="highlight"><pre><span></span><span class="k">fix </span><span class="nv nv-Identifier">ID</span><span class="w"> </span><span class="nv nv-Identifier">group-ID</span><span class="w"> </span><span class="n">style</span><span class="w"> </span><span class="n">[tabstyle]</span><span class="w"> </span><span class="n">[N]</span><span class="w"> </span><span class="n">face</span><span class="w"> </span><span class="n">args</span><span class="w"> </span><span class="n">...</span><span class="w"> </span><span class="n">keyword</span><span class="w"> </span><span class="n">value</span><span class="w"> </span><span class="n">...</span>
|
||
</pre></div>
|
||
</div>
|
||
<ul class="simple">
|
||
<li><p>ID, group-ID are documented in <a class="reference internal" href="fix.html"><span class="doc">fix</span></a> command</p></li>
|
||
<li><p>style = <em>wall/lj93</em> or <em>wall/lj126</em> or <em>wall/lj1043</em> or <em>wall/colloid</em> or <em>wall/harmonic</em> or <em>wall/lepton</em> or <em>wall/morse</em> or <em>wall/table</em></p></li>
|
||
<li><p>tabstyle = <em>linear</em> or <em>spline</em> = method of table interpolation (only applies to <em>wall/table</em>)</p></li>
|
||
<li><p>N = use N values in <em>linear</em> or <em>spline</em> interpolation (only applies to <em>wall/table</em>)</p></li>
|
||
<li><p>one or more face/arg pairs may be appended</p></li>
|
||
<li><p>face = <em>xlo</em> or <em>xhi</em> or <em>ylo</em> or <em>yhi</em> or <em>zlo</em> or <em>zhi</em></p></li>
|
||
</ul>
|
||
<ul>
|
||
<li><p>args for styles <em>lj93</em> or <em>lj126</em> or <em>lj1043</em> or <em>colloid</em> or <em>harmonic</em></p>
|
||
<pre class="literal-block">args = coord epsilon sigma cutoff
|
||
coord = position of wall = EDGE or constant or variable
|
||
EDGE = current lo or hi edge of simulation box
|
||
constant = number like 0.0 or -30.0 (distance units)
|
||
variable = <a class="reference internal" href="variable.html"><span class="doc">equal-style variable</span></a> like v_x or v_wiggle
|
||
epsilon = strength factor for wall-particle interaction (energy or energy/distance^2 units)
|
||
epsilon can be a variable (see below)
|
||
sigma = size factor for wall-particle interaction (distance units)
|
||
sigma can be a variable (see below)
|
||
cutoff = distance from wall at which wall-particle interactions are cut off (distance units)</pre>
|
||
</li>
|
||
<li><p>args for style <em>lepton</em></p>
|
||
<pre class="literal-block">args = coord expression cutoff
|
||
coord = position of wall = EDGE or constant or variable
|
||
EDGE = current lo or hi edge of simulation box
|
||
constant = number like 0.0 or -30.0 (distance units)
|
||
variable = <a class="reference internal" href="variable.html"><span class="doc">equal-style variable</span></a> like v_x or v_wiggle
|
||
expression = Lepton expression for the potential (energy units)
|
||
cutoff = distance from wall at which wall-particle interactions are cut off (distance units)</pre>
|
||
</li>
|
||
<li><p>args for style <em>morse</em></p>
|
||
<pre class="literal-block">args = coord D_0 alpha r_0 cutoff
|
||
coord = position of wall = EDGE or constant or variable
|
||
EDGE = current lo or hi edge of simulation box
|
||
constant = number like 0.0 or -30.0 (distance units)
|
||
variable = <a class="reference internal" href="variable.html"><span class="doc">equal-style variable</span></a> like v_x or v_wiggle
|
||
D_0 = depth of the potential (energy units)
|
||
D_0 can be a variable (see below)
|
||
alpha = width factor for wall-particle interaction (1/distance units)
|
||
alpha can be a variable (see below)
|
||
r_0 = distance of the potential minimum from the face of region (distance units)
|
||
r_0 can be a variable (see below)
|
||
cutoff = distance from wall at which wall-particle interactions are cut off (distance units)</pre>
|
||
</li>
|
||
<li><p>args for style <em>table</em></p>
|
||
<pre class="literal-block">args = coord filename keyword cutoff
|
||
coord = position of wall = EDGE or constant or variable
|
||
EDGE = current lo or hi edge of simulation box
|
||
constant = number like 0.0 or -30.0 (distance units)
|
||
variable = <a class="reference internal" href="variable.html"><span class="doc">equal-style variable</span></a> like v_x or v_wiggle
|
||
filename = file containing tabulated energy and force values
|
||
keyword = section identifier to select a specific table in table file
|
||
cutoff = distance from wall at which wall-particle interactions are cut off (distance units)</pre>
|
||
</li>
|
||
<li><p>zero or more keyword/value pairs may be appended</p></li>
|
||
<li><p>keyword = <em>units</em> or <em>fld</em> or <em>pbc</em></p>
|
||
<pre class="literal-block"><em>units</em> value = <em>lattice</em> or <em>box</em>
|
||
<em>lattice</em> = the wall position is defined in lattice units
|
||
<em>box</em> = the wall position is defined in simulation box units
|
||
<em>fld</em> value = <em>yes</em> or <em>no</em>
|
||
<em>yes</em> = invoke the wall constraint to be compatible with implicit FLD
|
||
<em>no</em> = invoke the wall constraint in the normal way
|
||
<em>pbc</em> value = <em>yes</em> or <em>no</em>
|
||
<em>yes</em> = allow periodic boundary in a wall dimension
|
||
<em>no</em> = require non-perioidic boundaries in any wall dimension</pre>
|
||
</li>
|
||
</ul>
|
||
</section>
|
||
<section id="examples">
|
||
<h2>Examples<a class="headerlink" href="#examples" title="Link to this heading"></a></h2>
|
||
<div class="highlight-LAMMPS notranslate"><div class="highlight"><pre><span></span><span class="k">fix </span><span class="nv nv-Identifier">wallhi</span><span class="w"> </span><span class="nv nv-Identifier">all</span><span class="w"> </span><span class="n">wall</span><span class="o">/</span><span class="n">lj93</span><span class="w"> </span><span class="n">xlo</span><span class="w"> </span><span class="o">-</span><span class="m">1.0</span><span class="w"> </span><span class="m">1.0</span><span class="w"> </span><span class="m">1.0</span><span class="w"> </span><span class="m">2.5</span><span class="w"> </span><span class="n">units</span><span class="w"> </span><span class="n">box</span>
|
||
<span class="k">fix </span><span class="nv nv-Identifier">wallhi</span><span class="w"> </span><span class="nv nv-Identifier">all</span><span class="w"> </span><span class="n">wall</span><span class="o">/</span><span class="n">lj93</span><span class="w"> </span><span class="n">xhi</span><span class="w"> </span><span class="n">EDGE</span><span class="w"> </span><span class="m">1.0</span><span class="w"> </span><span class="m">1.0</span><span class="w"> </span><span class="m">2.5</span>
|
||
<span class="k">fix </span><span class="nv nv-Identifier">wallhi</span><span class="w"> </span><span class="nv nv-Identifier">all</span><span class="w"> </span><span class="n">wall</span><span class="o">/</span><span class="n">harmonic</span><span class="w"> </span><span class="n">xhi</span><span class="w"> </span><span class="n">EDGE</span><span class="w"> </span><span class="m">100.0</span><span class="w"> </span><span class="m">0.0</span><span class="w"> </span><span class="m">4.0</span><span class="w"> </span><span class="n">units</span><span class="w"> </span><span class="n">box</span>
|
||
<span class="k">fix </span><span class="nv nv-Identifier">wallhi</span><span class="w"> </span><span class="nv nv-Identifier">all</span><span class="w"> </span><span class="n">wall</span><span class="o">/</span><span class="n">morse</span><span class="w"> </span><span class="n">xhi</span><span class="w"> </span><span class="n">EDGE</span><span class="w"> </span><span class="m">1.0</span><span class="w"> </span><span class="m">1.0</span><span class="w"> </span><span class="m">1.0</span><span class="w"> </span><span class="m">2.5</span><span class="w"> </span><span class="n">units</span><span class="w"> </span><span class="n">box</span>
|
||
<span class="k">fix </span><span class="nv nv-Identifier">wallhi</span><span class="w"> </span><span class="nv nv-Identifier">all</span><span class="w"> </span><span class="n">wall</span><span class="o">/</span><span class="n">lj126</span><span class="w"> </span><span class="n">v_wiggle</span><span class="w"> </span><span class="m">23.2</span><span class="w"> </span><span class="m">1.0</span><span class="w"> </span><span class="m">1.0</span><span class="w"> </span><span class="m">2.5</span>
|
||
<span class="k">fix </span><span class="nv nv-Identifier">zwalls</span><span class="w"> </span><span class="nv nv-Identifier">all</span><span class="w"> </span><span class="n">wall</span><span class="o">/</span><span class="n">colloid</span><span class="w"> </span><span class="n">zlo</span><span class="w"> </span><span class="m">0.0</span><span class="w"> </span><span class="m">1.0</span><span class="w"> </span><span class="m">1.0</span><span class="w"> </span><span class="m">0.858</span><span class="w"> </span><span class="n">zhi</span><span class="w"> </span><span class="m">40.0</span><span class="w"> </span><span class="m">1.0</span><span class="w"> </span><span class="m">1.0</span><span class="w"> </span><span class="m">0.858</span>
|
||
<span class="k">fix </span><span class="nv nv-Identifier">xwall</span><span class="w"> </span><span class="nv nv-Identifier">mobile</span><span class="w"> </span><span class="n">wall</span><span class="o">/</span><span class="n">table</span><span class="w"> </span><span class="n">spline</span><span class="w"> </span><span class="m">200</span><span class="w"> </span><span class="n">EDGE</span><span class="w"> </span><span class="o">-</span><span class="m">5.0</span><span class="w"> </span><span class="n">walltab.dat</span><span class="w"> </span><span class="n">HARMONIC</span><span class="w"> </span><span class="m">4.0</span>
|
||
<span class="k">fix </span><span class="nv nv-Identifier">xwalls</span><span class="w"> </span><span class="nv nv-Identifier">mobile</span><span class="w"> </span><span class="n">wall</span><span class="o">/</span><span class="n">lepton</span><span class="w"> </span><span class="n">xlo</span><span class="w"> </span><span class="o">-</span><span class="m">5.0</span><span class="w"> </span><span class="s">"k*(r-rc)^2;k=100.0"</span><span class="w"> </span><span class="m">4.0</span><span class="w"> </span><span class="n">xhi</span><span class="w"> </span><span class="m">5.0</span><span class="w"> </span><span class="s">"k*(r-rc)^2;k=100.0"</span><span class="w"> </span><span class="m">4.0</span>
|
||
</pre></div>
|
||
</div>
|
||
</section>
|
||
<section id="description">
|
||
<h2>Description<a class="headerlink" href="#description" title="Link to this heading"></a></h2>
|
||
<p>Bound the simulation domain on one or more of its faces with a flat
|
||
wall that interacts with the atoms in the group by generating a force
|
||
on the atom in a direction perpendicular to the wall. The energy of
|
||
wall-particle interactions depends on the style.</p>
|
||
<p>For style <em>wall/lj93</em>, the energy E is given by the 9-3 Lennard-Jones potential:</p>
|
||
<div class="math notranslate nohighlight">
|
||
\[E = \epsilon \left[ \frac{2}{15} \left(\frac{\sigma}{r}\right)^{9} -
|
||
\left(\frac{\sigma}{r}\right)^3 \right]
|
||
\qquad r < r_c\]</div>
|
||
<p>For style <em>wall/lj126</em>, the energy E is given by the 12-6 Lennard-Jones potential:</p>
|
||
<div class="math notranslate nohighlight">
|
||
\[E = 4 \epsilon \left[ \left(\frac{\sigma}{r}\right)^{12} -
|
||
\left(\frac{\sigma}{r}\right)^6 \right]
|
||
\qquad r < r_c\]</div>
|
||
<p>For style <em>wall/lj1043</em>, the energy E is given by the 10-4-3 Lennard-Jones potential:</p>
|
||
<div class="math notranslate nohighlight">
|
||
\[E = 2 \pi \epsilon \left[ \frac{2}{5} \left(\frac{\sigma}{r}\right)^{10} -
|
||
\left(\frac{\sigma}{r}\right)^4 -
|
||
\frac{\sqrt(2)\sigma^3}{3\left(r+\left(0.61/\sqrt(2)\right)\sigma\right)^3}\right]
|
||
\qquad r < r_c\]</div>
|
||
<p>For style <em>wall/colloid</em>, the energy E is given by an integrated form
|
||
of the <a class="reference internal" href="pair_colloid.html"><span class="doc">pair_style colloid</span></a> potential:</p>
|
||
<div class="math notranslate nohighlight">
|
||
\[\begin{split}E = & \epsilon \left[ \frac{\sigma^{6}}{7560}
|
||
\left(\frac{6R-D}{D^{7}} + \frac{D+8R}{(D+2R)^{7}} \right) \right. \\
|
||
& \left. - \frac{1}{6} \left(\frac{2R(D+R) + D(D+2R)
|
||
\left[ \ln D - \ln (D+2R) \right]}{D(D+2R)} \right) \right] \qquad r < r_c\end{split}\]</div>
|
||
<p>For style <em>wall/harmonic</em>, the energy E is given by a repulsive-only harmonic
|
||
spring potential:</p>
|
||
<div class="math notranslate nohighlight">
|
||
\[E = \epsilon \quad (r - r_c)^2 \qquad r < r_c\]</div>
|
||
<p>For style <em>wall/morse</em>, the energy E is given by a Morse potential:</p>
|
||
<div class="math notranslate nohighlight">
|
||
\[E = D_0 \left[ e^{- 2 \alpha (r - r_0)} - 2 e^{- \alpha (r - r_0)} \right]
|
||
\qquad r < r_c\]</div>
|
||
<div class="versionadded">
|
||
<p><span class="versionmodified added">Added in version 28Mar2023.</span></p>
|
||
</div>
|
||
<p>For style <em>wall/lepton</em>, the energy E is provided as an Lepton
|
||
expression string using “r” as the distance variable. The <a class="reference external" href="https://simtk.org/projects/lepton">Lepton
|
||
library</a>, that the <em>wall/lepton</em>
|
||
style interfaces with, evaluates this expression string at run time to
|
||
compute the wall-particle energy. It also creates an analytical
|
||
representation of the first derivative of this expression with respect
|
||
to “r” and then uses that to compute the force between the wall and
|
||
atoms in the fix group. The Lepton expression must be either enclosed
|
||
in quotes or must not contain any whitespace so that LAMMPS recognizes
|
||
it as a single keyword.</p>
|
||
<p>Optionally, the expression may use “rc” to refer to the cutoff distance
|
||
for the given wall. Further constants in the expression can be defined
|
||
in the same string as additional expressions separated by semicolons.
|
||
The expression “k*(r-rc)^2;k=100.0” represents a repulsive-only harmonic
|
||
spring as in fix <em>wall/harmonic</em> with a force constant <em>K</em> (same as
|
||
<span class="math notranslate nohighlight">\(\epsilon\)</span> above) of 100 energy units. More details on the Lepton
|
||
expression strings are given below.</p>
|
||
<div class="versionadded">
|
||
<p><span class="versionmodified added">Added in version 28Mar2023.</span></p>
|
||
</div>
|
||
<p>For style <em>wall/table</em>, the energy E and forces are determined from
|
||
interpolation tables listed in one or more files as a function of
|
||
distance. The interpolation tables are used to evaluate energy and
|
||
forces between particles and the wall similar to how analytic formulas
|
||
are used for the other wall styles.</p>
|
||
<p>The interpolation tables are created as a pre-computation by fitting
|
||
cubic splines to the file values and interpolating energy and force
|
||
values at each of <em>N</em> distances. During a simulation, the tables are
|
||
used to interpolate energy and force values as needed for each wall and
|
||
particle separated by a distance <em>R</em>. The interpolation is done in
|
||
one of two styles: <em>linear</em> or <em>spline</em>.</p>
|
||
<p>For the <em>linear</em> style, the distance <em>R</em> is used to find the 2
|
||
surrounding table values from which an energy or force is computed by
|
||
linear interpolation.</p>
|
||
<p>For the <em>spline</em> style, cubic spline coefficients are computed and
|
||
stored for each of the <em>N</em> values in the table, one set of splines for
|
||
energy, another for force. Note that these splines are different than
|
||
the ones used to pre-compute the <em>N</em> values. Those splines were fit
|
||
to the <em>Nfile</em> values in the tabulated file, where often <em>Nfile</em> <
|
||
<em>N</em>. The distance <em>R</em> is used to find the appropriate set of spline
|
||
coefficients which are used to evaluate a cubic polynomial which
|
||
computes the energy or force.</p>
|
||
<p>For each wall a filename and a keyword must be provided as in the
|
||
examples above. The filename specifies a file containing tabulated
|
||
energy and force values. The keyword specifies a section of the file.
|
||
The format of this file is described below.</p>
|
||
<p>In all cases, <em>r</em> is the distance from the particle to the wall at
|
||
position <em>coord</em>, and <span class="math notranslate nohighlight">\(r_c\)</span> is the <em>cutoff</em> distance at which the
|
||
particle and wall no longer interact. The energy of the wall
|
||
potential is shifted so that the wall-particle interaction energy is
|
||
0.0 at the cutoff distance.</p>
|
||
<p>Up to 6 walls or faces can be specified in a single command: <em>xlo</em>,
|
||
<em>xhi</em>, <em>ylo</em>, <em>yhi</em>, <em>zlo</em>, <em>zhi</em>. A <em>lo</em> face interacts with
|
||
particles near the lower side of the simulation box in that dimension.
|
||
A <em>hi</em> face interacts with particles near the upper side of the
|
||
simulation box in that dimension.</p>
|
||
<p>The position of each wall can be specified in one of 3 ways: as the
|
||
EDGE of the simulation box, as a constant value, or as a variable. If
|
||
EDGE is used, then the corresponding boundary of the current
|
||
simulation box is used. If a numeric constant is specified then the
|
||
wall is placed at that position in the appropriate dimension (x, y, or
|
||
z). In both the EDGE and constant cases, the wall will never move.
|
||
If the wall position is a variable, it should be specified as v_name,
|
||
where name is an <a class="reference internal" href="variable.html"><span class="doc">equal-style variable</span></a> name. In this
|
||
case the variable is evaluated each timestep and the result becomes
|
||
the current position of the reflecting wall. Equal-style variables
|
||
can specify formulas with various mathematical functions, and include
|
||
<a class="reference internal" href="thermo_style.html"><span class="doc">thermo_style</span></a> command keywords for the simulation
|
||
box parameters and timestep and elapsed time. Thus it is easy to
|
||
specify a time-dependent wall position. See examples below.</p>
|
||
<p>For the <em>wall/lj93</em> and <em>wall/lj126</em> and <em>wall/lj1043</em> styles,
|
||
<span class="math notranslate nohighlight">\(\epsilon\)</span> and <span class="math notranslate nohighlight">\(\sigma\)</span> are the usual Lennard-Jones
|
||
parameters, which determine the strength and size of the particle as it
|
||
interacts with the wall. Epsilon has energy units. Note that this
|
||
<span class="math notranslate nohighlight">\(\epsilon\)</span> and <span class="math notranslate nohighlight">\(\sigma\)</span> may be different than any
|
||
<span class="math notranslate nohighlight">\(\epsilon\)</span> or <span class="math notranslate nohighlight">\(\sigma\)</span> values defined for a pair style that
|
||
computes particle-particle interactions.</p>
|
||
<p>The <em>wall/lj93</em> interaction is derived by integrating over a 3d
|
||
half-lattice of Lennard-Jones 12/6 particles. The <em>wall/lj126</em>
|
||
interaction is effectively a harder, more repulsive wall interaction.
|
||
The <em>wall/lj1043</em> interaction is yet a different form of wall
|
||
interaction, described in Magda et al in <a class="reference internal" href="#magda"><span class="std std-ref">(Magda)</span></a>.</p>
|
||
<p>For the <em>wall/colloid</em> style, <em>R</em> is the radius of the colloid particle,
|
||
<em>D</em> is the distance from the surface of the colloid particle to the wall
|
||
(r-R), and <span class="math notranslate nohighlight">\(\sigma\)</span> is the size of a constituent LJ particle
|
||
inside the colloid particle and wall. Note that the cutoff distance Rc
|
||
in this case is the distance from the colloid particle center to the
|
||
wall. The prefactor <span class="math notranslate nohighlight">\(\epsilon\)</span> can be thought of as an effective
|
||
Hamaker constant with energy units for the strength of the colloid-wall
|
||
interaction. More specifically, the <span class="math notranslate nohighlight">\(\epsilon\)</span> prefactor is
|
||
<span class="math notranslate nohighlight">\(4\pi^2 \rho_{wall} \rho_{colloid} \epsilon \sigma^6\)</span>, where
|
||
<span class="math notranslate nohighlight">\(\epsilon\)</span> and <span class="math notranslate nohighlight">\(\sigma\)</span> are the LJ parameters for the
|
||
constituent LJ particles. <span class="math notranslate nohighlight">\(\rho_{wall}\)</span> and <span class="math notranslate nohighlight">\(\rho_{colloid}\)</span>
|
||
are the number density of the constituent particles, in the wall and
|
||
colloid respectively, in units of 1/volume.</p>
|
||
<p>The <em>wall/colloid</em> interaction is derived by integrating over
|
||
constituent LJ particles of size <span class="math notranslate nohighlight">\(\sigma\)</span> within the colloid
|
||
particle and a 3d half-lattice of Lennard-Jones 12/6 particles of size
|
||
<span class="math notranslate nohighlight">\(\sigma\)</span> in the wall. As mentioned in the preceding paragraph,
|
||
the density of particles in the wall and colloid can be different, as
|
||
specified by the <span class="math notranslate nohighlight">\(\epsilon\)</span> prefactor.</p>
|
||
<p>For the <em>wall/harmonic</em> style, <span class="math notranslate nohighlight">\(\epsilon\)</span> is effectively the spring
|
||
constant K, and has units (energy/distance^2). The input parameter
|
||
<span class="math notranslate nohighlight">\(\sigma\)</span> is ignored. The minimum energy position of the harmonic
|
||
spring is at the <em>cutoff</em>. This is a repulsive-only spring since the
|
||
interaction is truncated at the <em>cutoff</em></p>
|
||
<p>For the <em>wall/morse</em> style, the three parameters are in this order:
|
||
<span class="math notranslate nohighlight">\(D_0\)</span> the depth of the potential, <span class="math notranslate nohighlight">\(\alpha\)</span> the width
|
||
parameter, and <span class="math notranslate nohighlight">\(r_0\)</span> the location of the minimum. <span class="math notranslate nohighlight">\(D_0\)</span> has
|
||
energy units, <span class="math notranslate nohighlight">\(\alpha\)</span> inverse distance units, and <span class="math notranslate nohighlight">\(r_0\)</span>
|
||
distance units.</p>
|
||
<p>For any wall that supports them, the <span class="math notranslate nohighlight">\(\epsilon\)</span> and/or
|
||
<span class="math notranslate nohighlight">\(\sigma\)</span> and/or <span class="math notranslate nohighlight">\(\alpha\)</span> parameter can be specified as an
|
||
<a class="reference internal" href="variable.html"><span class="doc">equal-style variable</span></a>, in which case it should be
|
||
specified as v_name, where name is the variable name. As with a
|
||
variable wall position, the variable is evaluated each timestep and the
|
||
result becomes the current epsilon or sigma of the wall. Equal-style
|
||
variables can specify formulas with various mathematical functions, and
|
||
include <a class="reference internal" href="thermo_style.html"><span class="doc">thermo_style</span></a> command keywords for the
|
||
simulation box parameters and timestep and elapsed time. Thus it is
|
||
easy to specify a time-dependent wall interaction.</p>
|
||
<div class="admonition note">
|
||
<p class="admonition-title">Note</p>
|
||
<p>For all of the styles, you must ensure that r is always > 0 for
|
||
all particles in the group, or LAMMPS will generate an error. This
|
||
means you cannot start your simulation with particles at the wall
|
||
position <em>coord</em> (r = 0) or with particles on the wrong side of the
|
||
wall (r < 0). For the <em>wall/lj93</em> and <em>wall/lj126</em> styles, the energy
|
||
of the wall/particle interaction (and hence the force on the particle)
|
||
blows up as r -> 0. The <em>wall/colloid</em> style is even more
|
||
restrictive, since the energy blows up as D = r-R -> 0. This means
|
||
the finite-size particles of radius R must be a distance larger than R
|
||
from the wall position <em>coord</em>. The <em>harmonic</em> style is a softer
|
||
potential and does not blow up as r -> 0, but you must use a large
|
||
enough <span class="math notranslate nohighlight">\(\epsilon\)</span> that particles always reamin on the correct side of
|
||
the wall (r > 0).</p>
|
||
</div>
|
||
<p>The <em>units</em> keyword determines the meaning of the distance units used
|
||
to define a wall position, but only when a numeric constant or
|
||
variable is used. It is not relevant when EDGE is used to specify a
|
||
face position. In the variable case, the variable is assumed to
|
||
produce a value compatible with the <em>units</em> setting you specify.</p>
|
||
<p>A <em>box</em> value selects standard distance units as defined by the
|
||
<a class="reference internal" href="units.html"><span class="doc">units</span></a> command, e.g. Angstroms for units = real or metal.
|
||
A <em>lattice</em> value means the distance units are in lattice spacings.
|
||
The <a class="reference internal" href="lattice.html"><span class="doc">lattice</span></a> command must have been previously used to
|
||
define the lattice spacings.</p>
|
||
<p>The <em>fld</em> keyword can be used with a <em>yes</em> setting to invoke the wall
|
||
constraint before pairwise interactions are computed. This allows an
|
||
implicit FLD model using <a class="reference internal" href="pair_lubricateU.html"><span class="doc">pair_style lubricateU</span></a>
|
||
to include the wall force in its calculations. If the setting is <em>no</em>,
|
||
wall forces are imposed after pairwise interactions, in the usual
|
||
manner.</p>
|
||
<p>The <em>pbc</em> keyword can be used with a <em>yes</em> setting to allow walls to be
|
||
specified in a periodic dimension. See the <a class="reference internal" href="boundary.html"><span class="doc">boundary</span></a>
|
||
command for options on simulation box boundaries. The default for <em>pbc</em>
|
||
is <em>no</em>, which means the system must be non-periodic when using a wall.
|
||
But you may wish to use a periodic box. E.g. to allow some particles to
|
||
interact with the wall via the fix group-ID, and others to pass through
|
||
it and wrap around a periodic box. In this case you should ensure that
|
||
the wall is sufficiently far enough away from the box boundary. If you
|
||
do not, then particles may interact with both the wall and with periodic
|
||
images on the other side of the box, which is probably not what you
|
||
want.</p>
|
||
<hr class="docutils" />
|
||
<p>Here are examples of variable definitions that move the wall position
|
||
in a time-dependent fashion using equal-style
|
||
<a class="reference internal" href="variable.html"><span class="doc">variables</span></a>. The wall interaction parameters (epsilon,
|
||
sigma) could be varied with additional variable definitions.</p>
|
||
<div class="highlight-LAMMPS notranslate"><div class="highlight"><pre><span></span><span class="k">variable </span><span class="nv nv-Identifier">ramp</span><span class="w"> </span><span class="n">equal</span><span class="w"> </span><span class="n">ramp</span><span class="nv">(0,10)</span>
|
||
<span class="k">fix </span><span class="nv nv-Identifier">1</span><span class="w"> </span><span class="nv nv-Identifier">all</span><span class="w"> </span><span class="n">wall</span><span class="w"> </span><span class="n">xlo</span><span class="w"> </span><span class="n">v_ramp</span><span class="w"> </span><span class="m">1.0</span><span class="w"> </span><span class="m">1.0</span><span class="w"> </span><span class="m">2.5</span>
|
||
|
||
<span class="k">variable </span><span class="nv nv-Identifier">linear</span><span class="w"> </span><span class="n">equal</span><span class="w"> </span><span class="n">vdisplace</span><span class="nv">(0,20)</span>
|
||
<span class="k">fix </span><span class="nv nv-Identifier">1</span><span class="w"> </span><span class="nv nv-Identifier">all</span><span class="w"> </span><span class="n">wall</span><span class="w"> </span><span class="n">xlo</span><span class="w"> </span><span class="n">v_linear</span><span class="w"> </span><span class="m">1.0</span><span class="w"> </span><span class="m">1.0</span><span class="w"> </span><span class="m">2.5</span>
|
||
|
||
<span class="k">variable </span><span class="nv nv-Identifier">wiggle</span><span class="w"> </span><span class="n">equal</span><span class="w"> </span><span class="n">swiggle</span><span class="nv">(0.0,5.0,3.0)</span>
|
||
<span class="k">fix </span><span class="nv nv-Identifier">1</span><span class="w"> </span><span class="nv nv-Identifier">all</span><span class="w"> </span><span class="n">wall</span><span class="w"> </span><span class="n">xlo</span><span class="w"> </span><span class="n">v_wiggle</span><span class="w"> </span><span class="m">1.0</span><span class="w"> </span><span class="m">1.0</span><span class="w"> </span><span class="m">2.5</span>
|
||
|
||
<span class="k">variable </span><span class="nv nv-Identifier">wiggle</span><span class="w"> </span><span class="n">equal</span><span class="w"> </span><span class="n">cwiggle</span><span class="nv">(0.0,5.0,3.0)</span>
|
||
<span class="k">fix </span><span class="nv nv-Identifier">1</span><span class="w"> </span><span class="nv nv-Identifier">all</span><span class="w"> </span><span class="n">wall</span><span class="w"> </span><span class="n">xlo</span><span class="w"> </span><span class="n">v_wiggle</span><span class="w"> </span><span class="m">1.0</span><span class="w"> </span><span class="m">1.0</span><span class="w"> </span><span class="m">2.5</span>
|
||
</pre></div>
|
||
</div>
|
||
<p>The <em>ramp(lo,hi)</em> function adjusts the wall position linearly from <em>lo</em> to
|
||
<em>hi</em> over the course of a run. The <em>vdisplace(c0,velocity)</em> function does
|
||
something similar using the equation <em>position = c0 + velocity*delta</em>,
|
||
where <em>delta</em> is the elapsed time.</p>
|
||
<p>The <em>swiggle(c0,A,period)</em> function causes the wall position to
|
||
oscillate sinusoidally according to this equation, where <em>omega = 2 PI
|
||
/ period</em>:</p>
|
||
<pre class="literal-block">position = c0 + A sin(omega*delta)</pre>
|
||
<p>The <em>cwiggle(c0,A,period)</em> function causes the wall position to
|
||
oscillate sinusoidally according to this equation, which will have an
|
||
initial wall velocity of 0.0, and thus may impose a gentler
|
||
perturbation on the particles:</p>
|
||
<pre class="literal-block">position = c0 + A (1 - cos(omega*delta))</pre>
|
||
</section>
|
||
<hr class="docutils" />
|
||
<section id="lepton-expression-syntax-and-features">
|
||
<h2>Lepton expression syntax and features<a class="headerlink" href="#lepton-expression-syntax-and-features" title="Link to this heading"></a></h2>
|
||
<p>Lepton supports the following operators in expressions:</p>
|
||
<table class="docutils align-default">
|
||
<tbody>
|
||
<tr class="row-odd"><td><p>+</p></td>
|
||
<td><p>Add</p></td>
|
||
<td></td>
|
||
<td><p>-</p></td>
|
||
<td><p>Subtract</p></td>
|
||
<td></td>
|
||
<td><p>*</p></td>
|
||
<td><p>Multiply</p></td>
|
||
<td></td>
|
||
<td><p>/</p></td>
|
||
<td><p>Divide</p></td>
|
||
<td></td>
|
||
<td><p>^</p></td>
|
||
<td><p>Power</p></td>
|
||
</tr>
|
||
</tbody>
|
||
</table>
|
||
<p>The following mathematical functions are available:</p>
|
||
<table class="docutils align-default">
|
||
<tbody>
|
||
<tr class="row-odd"><td><p>sqrt(x)</p></td>
|
||
<td><p>Square root</p></td>
|
||
<td><p>exp(x)</p></td>
|
||
<td><p>Exponential</p></td>
|
||
</tr>
|
||
<tr class="row-even"><td><p>log(x)</p></td>
|
||
<td><p>Natural logarithm</p></td>
|
||
<td><p>sin(x)</p></td>
|
||
<td><p>Sine (angle in radians)</p></td>
|
||
</tr>
|
||
<tr class="row-odd"><td><p>cos(x)</p></td>
|
||
<td><p>Cosine (angle in radians)</p></td>
|
||
<td><p>sec(x)</p></td>
|
||
<td><p>Secant (angle in radians)</p></td>
|
||
</tr>
|
||
<tr class="row-even"><td><p>csc(x)</p></td>
|
||
<td><p>Cosecant (angle in radians)</p></td>
|
||
<td><p>tan(x)</p></td>
|
||
<td><p>Tangent (angle in radians)</p></td>
|
||
</tr>
|
||
<tr class="row-odd"><td><p>cot(x)</p></td>
|
||
<td><p>Cotangent (angle in radians)</p></td>
|
||
<td><p>asin(x)</p></td>
|
||
<td><p>Inverse sine (in radians)</p></td>
|
||
</tr>
|
||
<tr class="row-even"><td><p>acos(x)</p></td>
|
||
<td><p>Inverse cosine (in radians)</p></td>
|
||
<td><p>atan(x)</p></td>
|
||
<td><p>Inverse tangent (in radians)</p></td>
|
||
</tr>
|
||
<tr class="row-odd"><td><p>sinh(x)</p></td>
|
||
<td><p>Hyperbolic sine</p></td>
|
||
<td><p>cosh(x)</p></td>
|
||
<td><p>Hyperbolic cosine</p></td>
|
||
</tr>
|
||
<tr class="row-even"><td><p>tanh(x)</p></td>
|
||
<td><p>Hyperbolic tangent</p></td>
|
||
<td><p>erf(x)</p></td>
|
||
<td><p>Error function</p></td>
|
||
</tr>
|
||
<tr class="row-odd"><td><p>erfc(x)</p></td>
|
||
<td><p>Complementary Error function</p></td>
|
||
<td><p>abs(x)</p></td>
|
||
<td><p>Absolute value</p></td>
|
||
</tr>
|
||
<tr class="row-even"><td><p>min(x,y)</p></td>
|
||
<td><p>Minimum of two values</p></td>
|
||
<td><p>max(x,y)</p></td>
|
||
<td><p>Maximum of two values</p></td>
|
||
</tr>
|
||
<tr class="row-odd"><td><p>delta(x)</p></td>
|
||
<td><p>delta(x) is 1 for <cite>x = 0</cite>, otherwise 0</p></td>
|
||
<td><p>step(x)</p></td>
|
||
<td><p>step(x) is 0 for <cite>x < 0</cite>, otherwise 1</p></td>
|
||
</tr>
|
||
</tbody>
|
||
</table>
|
||
<p>Numbers may be given in either decimal or exponential form. All of the
|
||
following are valid numbers: <cite>5</cite>, <cite>-3.1</cite>, <cite>1e6</cite>, and <cite>3.12e-2</cite>.</p>
|
||
<p>As an extension to the standard Lepton syntax, it is also possible to
|
||
use LAMMPS <a class="reference internal" href="variable.html"><span class="doc">variables</span></a> in the format “v_name”. Before
|
||
evaluating the expression, “v_name” will be replaced with the value of
|
||
the variable “name”. This is compatible with all kinds of scalar
|
||
variables, but not with vectors, arrays, local, or per-atom
|
||
variables. If necessary, a custom scalar variable needs to be defined
|
||
that can access the desired (single) item from a non-scalar variable.
|
||
As an example, the following lines will instruct LAMMPS to ramp
|
||
the force constant for a harmonic bond from 100.0 to 200.0 during the
|
||
next run:</p>
|
||
<div class="highlight-LAMMPS notranslate"><div class="highlight"><pre><span></span><span class="k">variable </span><span class="nv nv-Identifier">fconst</span><span class="w"> </span><span class="n">equal</span><span class="w"> </span><span class="n">ramp</span><span class="nv">(100.0, 200)</span>
|
||
<span class="k">bond_style</span><span class="w"> </span><span class="n">lepton</span>
|
||
<span class="k">bond_coeff</span><span class="w"> </span><span class="m">1</span><span class="w"> </span><span class="m">1.5</span><span class="w"> </span><span class="s">"v_fconst * (r^2)"</span>
|
||
</pre></div>
|
||
</div>
|
||
<p>An expression may be followed by definitions for intermediate values that appear in the
|
||
expression. A semicolon “;” is used as a delimiter between value definitions. For example,
|
||
the expression:</p>
|
||
<div class="highlight-C notranslate"><div class="highlight"><pre><span></span><span class="n">a</span><span class="o">^</span><span class="mi">2</span><span class="o">+</span><span class="n">a</span><span class="o">*</span><span class="n">b</span><span class="o">+</span><span class="n">b</span><span class="o">^</span><span class="mi">2</span><span class="p">;</span><span class="w"> </span><span class="n">a</span><span class="o">=</span><span class="n">a1</span><span class="o">+</span><span class="n">a2</span><span class="p">;</span><span class="w"> </span><span class="n">b</span><span class="o">=</span><span class="n">b1</span><span class="o">+</span><span class="n">b2</span>
|
||
</pre></div>
|
||
</div>
|
||
<p>is exactly equivalent to</p>
|
||
<div class="highlight-C notranslate"><div class="highlight"><pre><span></span><span class="p">(</span><span class="n">a1</span><span class="o">+</span><span class="n">a2</span><span class="p">)</span><span class="o">^</span><span class="mi">2</span><span class="o">+</span><span class="p">(</span><span class="n">a1</span><span class="o">+</span><span class="n">a2</span><span class="p">)</span><span class="o">*</span><span class="p">(</span><span class="n">b1</span><span class="o">+</span><span class="n">b2</span><span class="p">)</span><span class="o">+</span><span class="p">(</span><span class="n">b1</span><span class="o">+</span><span class="n">b2</span><span class="p">)</span><span class="o">^</span><span class="mi">2</span>
|
||
</pre></div>
|
||
</div>
|
||
<p>The definition of an intermediate value may itself involve other
|
||
intermediate values. Whitespace and quotation characters (’'’ and ‘”’)
|
||
are ignored. All uses of a value must appear <em>before</em> that value’s
|
||
definition. For efficiency reasons, the expression string is parsed,
|
||
optimized, and then stored in an internal, pre-parsed representation for
|
||
evaluation.</p>
|
||
<p>Evaluating a Lepton expression is typically between 2.5 and 5 times
|
||
slower than the corresponding compiled and optimized C++ code. If
|
||
additional speed or GPU acceleration (via GPU or KOKKOS) is required,
|
||
the interaction can be represented as a table. Suitable table files
|
||
can be created either internally using the <a class="reference internal" href="pair_write.html"><span class="doc">pair_write</span></a>
|
||
or <a class="reference internal" href="bond_write.html"><span class="doc">bond_write</span></a> command or through the Python scripts
|
||
in the <a class="reference internal" href="Tools.html#tabulate"><span class="std std-ref">tools/tabulate</span></a> folder.</p>
|
||
</section>
|
||
<hr class="docutils" />
|
||
<section id="table-file-format">
|
||
<h2>Table file format<a class="headerlink" href="#table-file-format" title="Link to this heading"></a></h2>
|
||
<p>Suitable tables for use with fix <em>wall/table</em> can be created by the
|
||
Python code in the <code class="docutils literal notranslate"><span class="pre">tools/tabulate</span></code> folder of the LAMMPS source code
|
||
distribution.</p>
|
||
<p>The format of a tabulated file is as follows (without the parenthesized
|
||
comments):</p>
|
||
<div class="highlight-none notranslate"><div class="highlight"><pre><span></span># Tabulated wall potential UNITS: real
|
||
|
||
HARMONIC (keyword is the first text on a line)
|
||
N 100 FP 200 200
|
||
(blank line)
|
||
1 0.04 1568.16 792.00 (index, distance to wall, energy, force)
|
||
2 0.08 1536.64 784.00
|
||
3 0.12 1505.44 776.00
|
||
...
|
||
99 3.96 0.16 8.00
|
||
100 4.00 0 0
|
||
</pre></div>
|
||
</div>
|
||
<p>A section begins with a non-blank line whose first character is not a
|
||
“#”; blank lines or lines starting with “#” can be used as comments
|
||
between sections. The first line begins with a keyword which identifies
|
||
the section. The line can contain additional text, but the initial text
|
||
must match the argument specified in the fix <em>wall/table</em> command. The
|
||
next line lists (in any order) one or more parameters for the table.
|
||
Each parameter is a keyword followed by one or more numeric values.</p>
|
||
<p>The parameter “N” is required and its value is the number of table
|
||
entries that follow. Note that this may be different than the <em>N</em>
|
||
specified in the fix <em>wall/table</em> command. Let Ntable = <em>N</em> in the fix
|
||
command, and Nfile = “N” in the tabulated file. What LAMMPS does is a
|
||
preliminary interpolation by creating splines using the Nfile tabulated
|
||
values as nodal points. It uses these to interpolate as needed to
|
||
generate energy and force values at Ntable different points. The
|
||
resulting tables of length Ntable are then used as described above, when
|
||
computing energy and force for wall-particle interactions. This means that
|
||
if you want the interpolation tables of length Ntable to match exactly
|
||
what is in the tabulated file (with effectively no preliminary
|
||
interpolation), you should set Ntable = Nfile.</p>
|
||
</section>
|
||
<hr class="docutils" />
|
||
<section id="restart-fix-modify-output-run-start-stop-minimize-info">
|
||
<h2>Restart, fix_modify, output, run start/stop, minimize info<a class="headerlink" href="#restart-fix-modify-output-run-start-stop-minimize-info" title="Link to this heading"></a></h2>
|
||
<p>No information about this fix is written to <a class="reference internal" href="restart.html"><span class="doc">binary restart files</span></a>.</p>
|
||
<p>The <a class="reference internal" href="fix_modify.html"><span class="doc">fix_modify</span></a> <em>energy</em> option is supported by
|
||
this fix to add the energy of interaction between atoms and all the
|
||
specified walls to the global potential energy of the system as part
|
||
of <a class="reference internal" href="thermo_style.html"><span class="doc">thermodynamic output</span></a>. The default setting
|
||
for this fix is <a class="reference internal" href="fix_modify.html"><span class="doc">fix_modify energy no</span></a>.</p>
|
||
<p>The <a class="reference internal" href="fix_modify.html"><span class="doc">fix_modify</span></a> <em>virial</em> option is supported by
|
||
this fix to add the contribution due to the interaction between atoms
|
||
and all the specified walls to both the global pressure and per-atom
|
||
stress of the system via the <a class="reference internal" href="compute_pressure.html"><span class="doc">compute pressure</span></a> and <a class="reference internal" href="compute_stress_atom.html"><span class="doc">compute stress/atom</span></a> commands. The former can be accessed by
|
||
<a class="reference internal" href="thermo_style.html"><span class="doc">thermodynamic output</span></a>. The default setting for
|
||
this fix is <a class="reference internal" href="fix_modify.html"><span class="doc">fix_modify virial no</span></a>.</p>
|
||
<p>The <a class="reference internal" href="fix_modify.html"><span class="doc">fix_modify</span></a> <em>respa</em> option is supported by this
|
||
fix. This allows to set at which level of the <a class="reference internal" href="run_style.html"><span class="doc">r-RESPA</span></a> integrator the fix is adding its forces. Default is the
|
||
outermost level.</p>
|
||
<p>This fix computes a global scalar energy and a global vector of forces,
|
||
which can be accessed by various <a class="reference internal" href="Howto_output.html"><span class="doc">output commands</span></a>.
|
||
Note that the scalar energy is the sum of interactions with all defined
|
||
walls. If you want the energy on a per-wall basis, you need to use
|
||
multiple fix wall commands. The length of the vector is equal to the
|
||
number of walls defined by the fix. Each vector value is the normal
|
||
force on a specific wall. Note that an outward force on a wall will be
|
||
a negative value for <em>lo</em> walls and a positive value for <em>hi</em> walls.
|
||
The scalar and vector values calculated by this fix are “extensive”.</p>
|
||
<p>No parameter of this fix can be used with the <em>start/stop</em> keywords of
|
||
the <a class="reference internal" href="run.html"><span class="doc">run</span></a> command.</p>
|
||
<p>The forces due to this fix are imposed during an energy minimization,
|
||
invoked by the <a class="reference internal" href="minimize.html"><span class="doc">minimize</span></a> command.</p>
|
||
<div class="admonition note">
|
||
<p class="admonition-title">Note</p>
|
||
<p>If you want the atom/wall interaction energy to be included in
|
||
the total potential energy of the system (the quantity being
|
||
minimized), you MUST enable the <a class="reference internal" href="fix_modify.html"><span class="doc">fix_modify</span></a> <em>energy</em>
|
||
option for this fix.</p>
|
||
</div>
|
||
<hr class="docutils" />
|
||
<p>Styles with a <em>gpu</em>, <em>intel</em>, <em>kk</em>, <em>omp</em>, or <em>opt</em> suffix are
|
||
functionally the same as the corresponding style without the suffix.
|
||
They have been optimized to run faster, depending on your available
|
||
hardware, as discussed on the <a class="reference internal" href="Speed_packages.html"><span class="doc">Accelerator packages</span></a>
|
||
page. The accelerated styles take the same arguments and should
|
||
produce the same results, except for round-off and precision issues.</p>
|
||
<p>These accelerated styles are part of the GPU, INTEL, KOKKOS,
|
||
OPENMP, and OPT packages, respectively. They are only enabled if
|
||
LAMMPS was built with those packages. See the <a class="reference internal" href="Build_package.html"><span class="doc">Build package</span></a> page for more info.</p>
|
||
<p>You can specify the accelerated styles explicitly in your input script
|
||
by including their suffix, or you can use the <a class="reference internal" href="Run_options.html"><span class="doc">-suffix command-line switch</span></a> when you invoke LAMMPS, or you can use the
|
||
<a class="reference internal" href="suffix.html"><span class="doc">suffix</span></a> command in your input script.</p>
|
||
<p>See the <a class="reference internal" href="Speed_packages.html"><span class="doc">Accelerator packages</span></a> page for more
|
||
instructions on how to use the accelerated styles effectively.</p>
|
||
</section>
|
||
<hr class="docutils" />
|
||
<section id="restrictions">
|
||
<h2>Restrictions<a class="headerlink" href="#restrictions" title="Link to this heading"></a></h2>
|
||
<p>Fix <em>wall/lepton</em> is part of the LEPTON package and only enabled if
|
||
LAMMPS was built with this package. See the <a class="reference internal" href="Build_package.html"><span class="doc">Build package</span></a> page for more info.</p>
|
||
</section>
|
||
<section id="related-commands">
|
||
<h2>Related commands<a class="headerlink" href="#related-commands" title="Link to this heading"></a></h2>
|
||
<p><a class="reference internal" href="fix_wall_reflect.html"><span class="doc">fix wall/reflect</span></a>,
|
||
<a class="reference internal" href="fix_wall_gran.html"><span class="doc">fix wall/gran</span></a>,
|
||
<a class="reference internal" href="fix_wall_region.html"><span class="doc">fix wall/region</span></a></p>
|
||
</section>
|
||
<section id="default">
|
||
<h2>Default<a class="headerlink" href="#default" title="Link to this heading"></a></h2>
|
||
<p>The option defaults units = lattice, fld = no, and pbc = no.</p>
|
||
<hr class="docutils" />
|
||
<p id="magda"><strong>(Magda)</strong> Magda, Tirrell, Davis, J Chem Phys, 83, 1888-1901 (1985);
|
||
erratum in JCP 84, 2901 (1986).</p>
|
||
</section>
|
||
</section>
|
||
|
||
|
||
</div>
|
||
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|
||
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