Files
lammps/doc/html/fix_ti_spring.html
2016-09-14 10:22:46 -06:00

575 lines
40 KiB
HTML

<!DOCTYPE html>
<!--[if IE 8]><html class="no-js lt-ie9" lang="en" > <![endif]-->
<!--[if gt IE 8]><!--> <html class="no-js" lang="en" > <!--<![endif]-->
<head>
<meta charset="utf-8">
<meta name="viewport" content="width=device-width, initial-scale=1.0">
<title>fix ti/spring command &mdash; LAMMPS documentation</title>
<link rel="stylesheet" href="_static/css/theme.css" type="text/css" />
<link rel="stylesheet" href="_static/sphinxcontrib-images/LightBox2/lightbox2/css/lightbox.css" type="text/css" />
<link rel="top" title="LAMMPS documentation" href="index.html"/>
<link rel="up" title="Fixes" href="fixes.html"/>
<link rel="next" title="fix tmd command" href="fix_tmd.html"/>
<link rel="prev" title="fix ti/rs command" href="fix_ti_rs.html"/>
<script src="_static/js/modernizr.min.js"></script>
</head>
<body class="wy-body-for-nav" role="document">
<div class="wy-grid-for-nav">
<nav data-toggle="wy-nav-shift" class="wy-nav-side">
<div class="wy-side-nav-search">
<a href="Manual.html" class="icon icon-home"> LAMMPS
</a>
<div role="search">
<form id="rtd-search-form" class="wy-form" action="search.html" method="get">
<input type="text" name="q" placeholder="Search docs" />
<input type="hidden" name="check_keywords" value="yes" />
<input type="hidden" name="area" value="default" />
</form>
</div>
</div>
<div class="wy-menu wy-menu-vertical" data-spy="affix" role="navigation" aria-label="main navigation">
<p class="caption"><span class="caption-text">User Documentation</span></p>
<ul>
<li class="toctree-l1"><a class="reference internal" href="Section_intro.html">1. Introduction</a></li>
<li class="toctree-l1"><a class="reference internal" href="Section_start.html">2. Getting Started</a></li>
<li class="toctree-l1"><a class="reference internal" href="Section_commands.html">3. Commands</a></li>
<li class="toctree-l1"><a class="reference internal" href="Section_packages.html">4. Packages</a></li>
<li class="toctree-l1"><a class="reference internal" href="Section_accelerate.html">5. Accelerating LAMMPS performance</a></li>
<li class="toctree-l1"><a class="reference internal" href="Section_howto.html">6. How-to discussions</a></li>
<li class="toctree-l1"><a class="reference internal" href="Section_example.html">7. Example problems</a></li>
<li class="toctree-l1"><a class="reference internal" href="Section_perf.html">8. Performance &amp; scalability</a></li>
<li class="toctree-l1"><a class="reference internal" href="Section_tools.html">9. Additional tools</a></li>
<li class="toctree-l1"><a class="reference internal" href="Section_modify.html">10. Modifying &amp; extending LAMMPS</a></li>
<li class="toctree-l1"><a class="reference internal" href="Section_python.html">11. Python interface to LAMMPS</a></li>
<li class="toctree-l1"><a class="reference internal" href="Section_errors.html">12. Errors</a></li>
<li class="toctree-l1"><a class="reference internal" href="Section_history.html">13. Future and history</a></li>
</ul>
<p class="caption"><span class="caption-text">Index</span></p>
<ul class="current">
<li class="toctree-l1"><a class="reference internal" href="tutorials.html">Tutorials</a></li>
<li class="toctree-l1"><a class="reference internal" href="commands.html">Commands</a></li>
<li class="toctree-l1 current"><a class="reference internal" href="fixes.html">Fixes</a><ul class="current">
<li class="toctree-l2"><a class="reference internal" href="fix_adapt.html">fix adapt command</a></li>
<li class="toctree-l2"><a class="reference internal" href="fix_adapt_fep.html">fix adapt/fep command</a></li>
<li class="toctree-l2"><a class="reference internal" href="fix_addforce.html">fix addforce command</a></li>
<li class="toctree-l2"><a class="reference internal" href="fix_addtorque.html">fix addtorque command</a></li>
<li class="toctree-l2"><a class="reference internal" href="fix_append_atoms.html">fix append/atoms command</a></li>
<li class="toctree-l2"><a class="reference internal" href="fix_atc.html">fix atc command</a></li>
<li class="toctree-l2"><a class="reference internal" href="fix_atom_swap.html">fix atom/swap command</a></li>
<li class="toctree-l2"><a class="reference internal" href="fix_ave_atom.html">fix ave/atom command</a></li>
<li class="toctree-l2"><a class="reference internal" href="fix_ave_chunk.html">fix ave/chunk command</a></li>
<li class="toctree-l2"><a class="reference internal" href="fix_ave_correlate.html">fix ave/correlate command</a></li>
<li class="toctree-l2"><a class="reference internal" href="fix_ave_correlate_long.html">fix ave/correlate/long command</a></li>
<li class="toctree-l2"><a class="reference internal" href="fix_ave_histo.html">fix ave/histo command</a></li>
<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>
<li class="toctree-l2"><a class="reference internal" href="fix_ave_time.html">fix ave/time command</a></li>
<li class="toctree-l2"><a class="reference internal" href="fix_aveforce.html">fix aveforce command</a></li>
<li class="toctree-l2"><a class="reference internal" href="fix_balance.html">fix balance command</a></li>
<li class="toctree-l2"><a class="reference internal" href="fix_bond_break.html">fix bond/break command</a></li>
<li class="toctree-l2"><a class="reference internal" href="fix_bond_create.html">fix bond/create command</a></li>
<li class="toctree-l2"><a class="reference internal" href="fix_bond_swap.html">fix bond/swap command</a></li>
<li class="toctree-l2"><a class="reference internal" href="fix_box_relax.html">fix box/relax command</a></li>
<li class="toctree-l2"><a class="reference internal" href="fix_colvars.html">fix colvars command</a></li>
<li class="toctree-l2"><a class="reference internal" href="fix_controller.html">fix controller command</a></li>
<li class="toctree-l2"><a class="reference internal" href="fix_deform.html">fix deform command</a></li>
<li class="toctree-l2"><a class="reference internal" href="fix_deform.html#fix-deform-kk-command">fix deform/kk command</a></li>
<li class="toctree-l2"><a class="reference internal" href="fix_deposit.html">fix deposit command</a></li>
<li class="toctree-l2"><a class="reference internal" href="fix_drag.html">fix drag command</a></li>
<li class="toctree-l2"><a class="reference internal" href="fix_drude.html">fix drude command</a></li>
<li class="toctree-l2"><a class="reference internal" href="fix_drude_transform.html">fix drude/transform/direct command</a></li>
<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>
<li class="toctree-l2"><a class="reference internal" href="fix_dt_reset.html">fix dt/reset command</a></li>
<li class="toctree-l2"><a class="reference internal" href="fix_efield.html">fix efield command</a></li>
<li class="toctree-l2"><a class="reference internal" href="fix_ehex.html">fix ehex command</a></li>
<li class="toctree-l2"><a class="reference internal" href="fix_enforce2d.html">fix enforce2d command</a></li>
<li class="toctree-l2"><a class="reference internal" href="fix_eos_cv.html">fix eos/cv command</a></li>
<li class="toctree-l2"><a class="reference internal" href="fix_eos_table.html">fix eos/table command</a></li>
<li class="toctree-l2"><a class="reference internal" href="fix_eos_table_rx.html">fix eos/table/rx command</a></li>
<li class="toctree-l2"><a class="reference internal" href="fix_evaporate.html">fix evaporate command</a></li>
<li class="toctree-l2"><a class="reference internal" href="fix_external.html">fix external command</a></li>
<li class="toctree-l2"><a class="reference internal" href="fix_flow_gauss.html">fix flow/gauss command</a></li>
<li class="toctree-l2"><a class="reference internal" href="fix_freeze.html">fix freeze command</a></li>
<li class="toctree-l2"><a class="reference internal" href="fix_gcmc.html">fix gcmc command</a></li>
<li class="toctree-l2"><a class="reference internal" href="fix_gld.html">fix gld command</a></li>
<li class="toctree-l2"><a class="reference internal" href="fix_gle.html">fix gle command</a></li>
<li class="toctree-l2"><a class="reference internal" href="fix_gravity.html">fix gravity command</a></li>
<li class="toctree-l2"><a class="reference internal" href="fix_gravity.html#fix-gravity-omp-command">fix gravity/omp command</a></li>
<li class="toctree-l2"><a class="reference internal" href="fix_heat.html">fix heat command</a></li>
<li class="toctree-l2"><a class="reference internal" href="fix_imd.html">fix imd command</a></li>
<li class="toctree-l2"><a class="reference internal" href="fix_indent.html">fix indent command</a></li>
<li class="toctree-l2"><a class="reference internal" href="fix_ipi.html">fix ipi command</a></li>
<li class="toctree-l2"><a class="reference internal" href="fix_langevin.html">fix langevin command</a></li>
<li class="toctree-l2"><a class="reference internal" href="fix_langevin.html#fix-langevin-kk-command">fix langevin/kk command</a></li>
<li class="toctree-l2"><a class="reference internal" href="fix_langevin_drude.html">fix langevin/drude command</a></li>
<li class="toctree-l2"><a class="reference internal" href="fix_langevin_eff.html">fix langevin/eff command</a></li>
<li class="toctree-l2"><a class="reference internal" href="fix_lb_fluid.html">fix lb/fluid command</a></li>
<li class="toctree-l2"><a class="reference internal" href="fix_lb_momentum.html">fix lb/momentum command</a></li>
<li class="toctree-l2"><a class="reference internal" href="fix_lb_pc.html">fix lb/pc command</a></li>
<li class="toctree-l2"><a class="reference internal" href="fix_lb_rigid_pc_sphere.html">fix lb/rigid/pc/sphere command</a></li>
<li class="toctree-l2"><a class="reference internal" href="fix_lb_viscous.html">fix lb/viscous command</a></li>
<li class="toctree-l2"><a class="reference internal" href="fix_lineforce.html">fix lineforce command</a></li>
<li class="toctree-l2"><a class="reference internal" href="fix_manifoldforce.html">fix manifoldforce command</a></li>
<li class="toctree-l2"><a class="reference internal" href="fix_meso.html">fix meso command</a></li>
<li class="toctree-l2"><a class="reference internal" href="fix_meso_stationary.html">fix meso/stationary command</a></li>
<li class="toctree-l2"><a class="reference internal" href="fix_momentum.html">fix momentum command</a></li>
<li class="toctree-l2"><a class="reference internal" href="fix_move.html">fix move command</a></li>
<li class="toctree-l2"><a class="reference internal" href="fix_msst.html">fix msst command</a></li>
<li class="toctree-l2"><a class="reference internal" href="fix_neb.html">fix neb command</a></li>
<li class="toctree-l2"><a class="reference internal" href="fix_nh.html">fix nvt command</a></li>
<li class="toctree-l2"><a class="reference internal" href="fix_nh.html#fix-nvt-intel-command">fix nvt/intel command</a></li>
<li class="toctree-l2"><a class="reference internal" href="fix_nh.html#fix-nvt-kk-command">fix nvt/kk command</a></li>
<li class="toctree-l2"><a class="reference internal" href="fix_nh.html#fix-nvt-omp-command">fix nvt/omp command</a></li>
<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-npt-intel-command">fix npt/intel command</a></li>
<li class="toctree-l2"><a class="reference internal" href="fix_nh.html#fix-npt-kk-command">fix npt/kk command</a></li>
<li class="toctree-l2"><a class="reference internal" href="fix_nh.html#fix-npt-omp-command">fix npt/omp command</a></li>
<li class="toctree-l2"><a class="reference internal" href="fix_nh.html#fix-nph-command">fix nph command</a></li>
<li class="toctree-l2"><a class="reference internal" href="fix_nh.html#fix-nph-kk-command">fix nph/kk command</a></li>
<li class="toctree-l2"><a class="reference internal" href="fix_nh.html#fix-nph-omp-command">fix nph/omp command</a></li>
<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_nph_asphere.html">fix nph/asphere command</a></li>
<li class="toctree-l2"><a class="reference internal" href="fix_nph_asphere.html#fix-nph-asphere-omp-command">fix nph/asphere/omp 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_nph_sphere.html#fix-nph-sphere-omp-command">fix nph/sphere/omp 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_nphug.html#fix-nphug-omp-command">fix nphug/omp 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_asphere.html#fix-npt-asphere-omp-command">fix npt/asphere/omp 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_sphere.html">fix npt/sphere command</a></li>
<li class="toctree-l2"><a class="reference internal" href="fix_npt_sphere.html#fix-npt-sphere-omp-command">fix npt/sphere/omp 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.html#fix-nve-intel-command">fix nve/intel command</a></li>
<li class="toctree-l2"><a class="reference internal" href="fix_nve.html#fix-nve-kk-command">fix nve/kk command</a></li>
<li class="toctree-l2"><a class="reference internal" href="fix_nve.html#fix-nve-omp-command">fix nve/omp 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.html#fix-nve-asphere-intel-command">fix nve/asphere/intel 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_body.html">fix nve/body 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_sphere.html#fix-nve-sphere-omp-command">fix nve/sphere/omp 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_nvt_asphere.html">fix nvt/asphere command</a></li>
<li class="toctree-l2"><a class="reference internal" href="fix_nvt_asphere.html#fix-nvt-asphere-omp-command">fix nvt/asphere/omp 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.html#fix-nvt-sllod-intel-command">fix nvt/sllod/intel command</a></li>
<li class="toctree-l2"><a class="reference internal" href="fix_nvt_sllod.html#fix-nvt-sllod-omp-command">fix nvt/sllod/omp 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_nvt_sphere.html#fix-nvt-sphere-omp-command">fix nvt/sphere/omp 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_phonon.html">fix phonon command</a></li>
<li class="toctree-l2"><a class="reference internal" href="fix_pimd.html">fix pimd 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_poems.html">fix poems</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_press_berendsen.html">fix press/berendsen 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_property_atom.html">fix property/atom 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-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_comb.html#fix-qeq-comb-omp-command">fix qeq/comb/omp command</a></li>
<li class="toctree-l2"><a class="reference internal" href="fix_qeq_reax.html">fix qeq/reax command</a></li>
<li class="toctree-l2"><a class="reference internal" href="fix_qeq_reax.html#fix-qeq-reax-kk-command">fix qeq/reax/kk 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_reax_bonds.html">fix reax/bonds command</a></li>
<li class="toctree-l2"><a class="reference internal" href="fix_reax_bonds.html#fix-reax-c-bonds-command">fix reax/c/bonds command</a></li>
<li class="toctree-l2"><a class="reference internal" href="fix_reaxc_species.html">fix reax/c/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_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_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-kk-command">fix setforce/kk 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_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_thermal_conductivity.html">fix thermal/conductivity command</a></li>
<li class="toctree-l2"><a class="reference internal" href="fix_ti_rs.html">fix ti/rs command</a></li>
<li class="toctree-l2 current"><a class="current reference internal" href="#">fix ti/spring 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="#description">Description</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="#restrictions">Restrictions</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_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-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_wall.html">fix wall/lj93 command</a></li>
<li class="toctree-l2"><a class="reference internal" href="fix_wall.html#fix-wall-lj126-command">fix wall/lj126 command</a></li>
<li class="toctree-l2"><a class="reference internal" href="fix_wall.html#fix-wall-lj1043-command">fix wall/lj1043 command</a></li>
<li class="toctree-l2"><a class="reference internal" href="fix_wall.html#fix-wall-colloid-command">fix wall/colloid command</a></li>
<li class="toctree-l2"><a class="reference internal" href="fix_wall.html#fix-wall-harmonic-command">fix wall/harmonic 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_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.html#fix-wall-reflect-kk-command">fix wall/reflect/kk 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>
</ul>
</li>
<li class="toctree-l1"><a class="reference internal" href="computes.html">Computes</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>
</ul>
</div>
&nbsp;
</nav>
<section data-toggle="wy-nav-shift" class="wy-nav-content-wrap">
<nav class="wy-nav-top" role="navigation" aria-label="top navigation">
<i data-toggle="wy-nav-top" class="fa fa-bars"></i>
<a href="Manual.html">LAMMPS</a>
</nav>
<div class="wy-nav-content">
<div class="rst-content">
<div role="navigation" aria-label="breadcrumbs navigation">
<ul class="wy-breadcrumbs">
<li><a href="Manual.html">Docs</a> &raquo;</li>
<li><a href="fixes.html">Fixes</a> &raquo;</li>
<li>fix ti/spring command</li>
<li class="wy-breadcrumbs-aside">
<a href="http://lammps.sandia.gov">Website</a>
<a href="Section_commands.html#comm">Commands</a>
</li>
</ul>
<hr/>
<div class="rst-footer-buttons" style="margin-bottom: 1em" role="navigation" aria-label="footer navigation">
<a href="fix_tmd.html" class="btn btn-neutral float-right" title="fix tmd command" accesskey="n">Next <span class="fa fa-arrow-circle-right"></span></a>
<a href="fix_ti_rs.html" class="btn btn-neutral" title="fix ti/rs command" accesskey="p"><span class="fa fa-arrow-circle-left"></span> Previous</a>
</div>
</div>
<div role="main" class="document" itemscope="itemscope" itemtype="http://schema.org/Article">
<div itemprop="articleBody">
<div class="section" id="fix-ti-spring-command">
<span id="index-0"></span><h1>fix ti/spring command</h1>
<div class="section" id="syntax">
<h2>Syntax</h2>
<pre class="literal-block">
fix ID group-ID ti/spring K t_switch t_equil keyword value ...
</pre>
<ul>
<li><p class="first">ID, group-ID are documented in <a class="reference internal" href="fix.html"><span class="doc">fix</span></a> command</p>
</li>
<li><p class="first">ti/spring = style name of this fix command</p>
</li>
<li><p class="first">K = spring constant (force/distance units)</p>
</li>
<li><p class="first">t_switch/t_equil = number of steps of the switching/equilibration procedure</p>
</li>
<li><p class="first">zero or more keyword/value pairs may be appended to args</p>
</li>
<li><p class="first">keyword = <em>function</em></p>
<pre class="literal-block">
<em>function</em> value = function-ID
function-ID = ID of the switching function (1 or 2)
</pre>
</li>
</ul>
<p><strong>Example:</strong></p>
<div class="highlight-default"><div class="highlight"><pre><span></span><span class="n">fix</span> <span class="n">ref</span> <span class="nb">all</span> <span class="n">ti</span><span class="o">/</span><span class="n">spring</span> <span class="mf">50.0</span> <span class="mi">2000</span> <span class="mi">1000</span> <span class="n">function</span> <span class="mi">2</span>
</pre></div>
</div>
</div>
<div class="section" id="description">
<h2>Description</h2>
<p>This fix allows you to compute the free energy of solids by performing
a thermodynamic integration between the solid of interest and an
Einstein crystal <a class="reference internal" href="#frenkel"><span class="std std-ref">(Frenkel)</span></a>. The thermodynamic integration
is performed using the nonequilibrium method of Adiabatic Switching
<a class="reference internal" href="#watanabe"><span class="std std-ref">(Watanabe,</span></a> <a class="reference internal" href="#dekoning96"><span class="std std-ref">de Koning96)</span></a>.</p>
<p>A spring force is applied independently to each atom in the group to
tether it to its initial position. The initial position for each atom
is its location at the time the fix command was issued. More details
about the springs are available in <a class="reference internal" href="fix_spring_self.html"><span class="doc">fix spring/self</span></a>. The forces on the atoms are
dynamically scaled during the simulation, the rescaling is done in the
following manner:</p>
<img alt="_images/fix_ti_spring_force.jpg" class="align-center" src="_images/fix_ti_spring_force.jpg" />
<p>where F_harm is the force due to the springs, F_solid is the total
force on the atoms due to the interatomic potential and lambda is the
coupling parameter of the thermodynamic integration.</p>
<p>The fix acts as follows: during the first <em>t_equil</em> steps after the
fix is defined the value of lambda is zero, this is the period to
equilibrate the system in the lambda = 0 state. After this the value
of lambda changes continuously from 0 to 1 according to the function
defined using the keyword <em>function</em> (described below), this is done
in <em>t_switch</em> steps. Then comes the second equilibration period of
<em>t_equil</em> to equilibrate the system in the lambda = 1 state. After
that the switching back to the lambda = 0 state is made using
<em>t_switch</em> timesteps and following the same switching function. After
this period the value of lambda is kept equal to zero and the fix has
no action in the dynamics of the system anymore.</p>
<p>The description of thermodynamic integration in both directions is
done in <a class="reference internal" href="#dekoning97"><span class="std std-ref">de Koning97</span></a>, the main reason is to try to
eliminate the dissipated heat due to the nonequilibrium process.</p>
<p>The <em>function</em> keyword allows the use of two different switching
rates, the option <em>1</em> results in a constant rescaling where the lambda
parameter changes at a constant rate during the switching time
according to the switching function</p>
<img alt="_images/fix_ti_spring_function_1.jpg" class="align-center" src="_images/fix_ti_spring_function_1.jpg" />
<p>where tau is the scaled time variable t/t_switch. The option number
<em>2</em> performs the switching at a rate defined by the following
switching function</p>
<img alt="_images/fix_ti_spring_function_2.jpg" class="align-center" src="_images/fix_ti_spring_function_2.jpg" />
<p>This function has zero slope as lambda approaches its extreme values
(0 and 1), according to (<a class="reference internal" href="#dekoning96"><span class="std std-ref">de Koning96)</span></a> this results in
smaller fluctuations on the integral to be computed on the
thermodynamic integration.</p>
<div class="admonition note">
<p class="first admonition-title">Note</p>
<p class="last">It is importante to keep the center of mass fixed during the
thermodynamic integration, a non-zero total velocity will result in
divergencies during the integration due to the fact that the atoms are
&#8216;attatched&#8217; to its equilibrium positions by the Einstein
crystal. Check the option <em>zero</em> of <a class="reference internal" href="fix_langevin.html"><span class="doc">fix langevin</span></a>
and <a class="reference internal" href="velocity.html"><span class="doc">velocity</span></a>. The use of the Nose-Hoover thermostat
(<a class="reference internal" href="fix_nh.html"><span class="doc">fix nvt</span></a>) is NOT recommended due to its well documented
issues with the canonical sampling of harmonic degrees of freedom
(notice that the <em>chain</em> option will NOT solve this problem). The
Langevin thermostat (<a class="reference external" href="fix_langevin.html&quot;">fix langevin</a>) works fine.</p>
</div>
<p><strong>Restart, fix_modify, output, run start/stop, minimize info:</strong></p>
<p>This fix writes the original coordinates of tethered atoms to <a class="reference internal" href="restart.html"><span class="doc">binary restart files</span></a>, so that the spring effect will be the
same in a restarted simulation. See the <a class="reference internal" href="read_restart.html"><span class="doc">read restart</span></a> command for info on how to re-specify a fix
in an input script that reads a restart file, so that the operation of
the fix continues in an uninterrupted fashion.</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 stored in the per-atom springs to the system&#8217;s
potential energy as part of <a class="reference internal" href="thermo_style.html"><span class="doc">thermodynamic output</span></a>.</p>
<p>This fix computes a global scalar and a global vector quantities which
can be accessed by various <a class="reference internal" href="Section_howto.html#howto-15"><span class="std std-ref">output commands</span></a>. The scalar is an energy which
is the sum of the spring energy for each atom, where the per-atom
energy is 0.5 * K * r^2. The vector has 2 positions, the first one is
the coupling parameter lambda and the second one is the time
derivative of lambda. The scalar and vector values calculated by this
fix are &#8220;extensive&#8221;.</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="first admonition-title">Note</p>
<p class="last">If you want the per-atom spring 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>
<p>An example script using this command is provided in the
examples/USER/misc/ti directory.</p>
</div>
<div class="section" id="related-commands">
<h2>Related commands</h2>
<p><a class="reference internal" href="fix_spring.html"><span class="doc">fix spring</span></a>, <a class="reference internal" href="fix_ti_rs.html"><span class="doc">fix ti/rs</span></a></p>
</div>
<div class="section" id="restrictions">
<h2>Restrictions</h2>
<p>This command is part of the USER-MISC package. It is only enabled if
LAMMPS was built with those packages. See the <a class="reference internal" href="Section_start.html#start-3"><span class="std std-ref">Making LAMMPS</span></a> section for more info.</p>
</div>
<div class="section" id="default">
<h2>Default</h2>
<p>The keyword default is function = 1.</p>
<hr class="docutils" />
<p id="frenkel"><strong>(Frenkel)</strong> Daan Frenkel and Anthony J. C. Ladd, J. Chem. Phys. 81, 3188
(1984).</p>
<p id="watanabe"><strong>(Watanabe)</strong> M. Watanabe and W. P. Reinhardt, Phys Rev Lett, 65, 3301 (1990).</p>
<p id="dekoning96"><strong>(de Koning 96)</strong> M. de Koning and A. Antonelli, Phys Rev E, 53, 465 (1996).</p>
<p id="dekoning97"><strong>(de Koning 97)</strong> M. de Koning and A. Antonelli, Phys Rev B, 55, 735 (1997).</p>
</div>
</div>
</div>
</div>
<footer>
<div class="rst-footer-buttons" role="navigation" aria-label="footer navigation">
<a href="fix_tmd.html" class="btn btn-neutral float-right" title="fix tmd command" accesskey="n">Next <span class="fa fa-arrow-circle-right"></span></a>
<a href="fix_ti_rs.html" class="btn btn-neutral" title="fix ti/rs command" accesskey="p"><span class="fa fa-arrow-circle-left"></span> Previous</a>
</div>
<hr/>
<div role="contentinfo">
<p>
&copy; Copyright 2013 Sandia Corporation.
</p>
</div>
Built with <a href="http://sphinx-doc.org/">Sphinx</a> using a <a href="https://github.com/snide/sphinx_rtd_theme">theme</a> provided by <a href="https://readthedocs.org">Read the Docs</a>.
</footer>
</div>
</div>
</section>
</div>
<script type="text/javascript">
var DOCUMENTATION_OPTIONS = {
URL_ROOT:'./',
VERSION:'',
COLLAPSE_INDEX:false,
FILE_SUFFIX:'.html',
HAS_SOURCE: true
};
</script>
<script type="text/javascript" src="_static/jquery.js"></script>
<script type="text/javascript" src="_static/underscore.js"></script>
<script type="text/javascript" src="_static/doctools.js"></script>
<script type="text/javascript" src="https://cdn.mathjax.org/mathjax/latest/MathJax.js?config=TeX-AMS-MML_HTMLorMML"></script>
<script type="text/javascript" src="_static/sphinxcontrib-images/LightBox2/lightbox2/js/jquery-1.11.0.min.js"></script>
<script type="text/javascript" src="_static/sphinxcontrib-images/LightBox2/lightbox2/js/lightbox.min.js"></script>
<script type="text/javascript" src="_static/sphinxcontrib-images/LightBox2/lightbox2-customize/jquery-noconflict.js"></script>
<script type="text/javascript" src="_static/js/theme.js"></script>
<script type="text/javascript">
jQuery(function () {
SphinxRtdTheme.StickyNav.enable();
});
</script>
</body>
</html>