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<title>compute centro/atom command &mdash; LAMMPS documentation</title>
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<div class="lammps_version">Version: <b>19 Nov 2024</b></div>
<div class="lammps_release">git info: </div>
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<p class="caption" role="heading"><span class="caption-text">User Guide</span></p>
<ul>
<li class="toctree-l1"><a class="reference internal" href="Intro.html">1. Introduction</a></li>
<li class="toctree-l1"><a class="reference internal" href="Install.html">2. Install LAMMPS</a></li>
<li class="toctree-l1"><a class="reference internal" href="Build.html">3. Build LAMMPS</a></li>
<li class="toctree-l1"><a class="reference internal" href="Run_head.html">4. Run LAMMPS</a></li>
<li class="toctree-l1"><a class="reference internal" href="Commands.html">5. Commands</a></li>
<li class="toctree-l1"><a class="reference internal" href="Packages.html">6. Optional packages</a></li>
<li class="toctree-l1"><a class="reference internal" href="Speed.html">7. Accelerate performance</a></li>
<li class="toctree-l1"><a class="reference internal" href="Howto.html">8. Howto discussions</a></li>
<li class="toctree-l1"><a class="reference internal" href="Examples.html">9. Example scripts</a></li>
<li class="toctree-l1"><a class="reference internal" href="Tools.html">10. Auxiliary tools</a></li>
<li class="toctree-l1"><a class="reference internal" href="Errors.html">11. Errors</a></li>
</ul>
<p class="caption" role="heading"><span class="caption-text">Programmer Guide</span></p>
<ul>
<li class="toctree-l1"><a class="reference internal" href="Library.html">1. LAMMPS Library Interfaces</a></li>
<li class="toctree-l1"><a class="reference internal" href="Python_head.html">2. Use Python with LAMMPS</a></li>
<li class="toctree-l1"><a class="reference internal" href="Modify.html">3. Modifying &amp; extending LAMMPS</a></li>
<li class="toctree-l1"><a class="reference internal" href="Developer.html">4. Information for Developers</a></li>
</ul>
<p class="caption" role="heading"><span class="caption-text">Command Reference</span></p>
<ul class="current">
<li class="toctree-l1"><a class="reference internal" href="commands_list.html">Commands</a></li>
<li class="toctree-l1"><a class="reference internal" href="fixes.html">Fix Styles</a></li>
<li class="toctree-l1 current"><a class="reference internal" href="computes.html">Compute Styles</a><ul class="current">
<li class="toctree-l2"><a class="reference internal" href="compute_ackland_atom.html">compute ackland/atom command</a></li>
<li class="toctree-l2"><a class="reference internal" href="compute_adf.html">compute adf command</a></li>
<li class="toctree-l2"><a class="reference internal" href="compute_angle.html">compute angle command</a></li>
<li class="toctree-l2"><a class="reference internal" href="compute_angle_local.html">compute angle/local command</a></li>
<li class="toctree-l2"><a class="reference internal" href="compute_angmom_chunk.html">compute angmom/chunk command</a></li>
<li class="toctree-l2"><a class="reference internal" href="compute_ave_sphere_atom.html">compute ave/sphere/atom command</a></li>
<li class="toctree-l2"><a class="reference internal" href="compute_basal_atom.html">compute basal/atom command</a></li>
<li class="toctree-l2"><a class="reference internal" href="compute_body_local.html">compute body/local command</a></li>
<li class="toctree-l2"><a class="reference internal" href="compute_bond.html">compute bond command</a></li>
<li class="toctree-l2"><a class="reference internal" href="compute_bond_local.html">compute bond/local command</a></li>
<li class="toctree-l2"><a class="reference internal" href="compute_born_matrix.html">compute born/matrix command</a></li>
<li class="toctree-l2 current"><a class="current reference internal" href="#">compute centro/atom 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="#output-info">Output 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="compute_chunk_atom.html">compute chunk/atom command</a></li>
<li class="toctree-l2"><a class="reference internal" href="compute_chunk_spread_atom.html">compute chunk/spread/atom command</a></li>
<li class="toctree-l2"><a class="reference internal" href="compute_cluster_atom.html">compute cluster/atom command</a></li>
<li class="toctree-l2"><a class="reference internal" href="compute_cluster_atom.html#compute-fragment-atom-command">compute fragment/atom command</a></li>
<li class="toctree-l2"><a class="reference internal" href="compute_cluster_atom.html#compute-aggregate-atom-command">compute aggregate/atom command</a></li>
<li class="toctree-l2"><a class="reference internal" href="compute_cna_atom.html">compute cna/atom command</a></li>
<li class="toctree-l2"><a class="reference internal" href="compute_cnp_atom.html">compute cnp/atom command</a></li>
<li class="toctree-l2"><a class="reference internal" href="compute_com.html">compute com command</a></li>
<li class="toctree-l2"><a class="reference internal" href="compute_com_chunk.html">compute com/chunk command</a></li>
<li class="toctree-l2"><a class="reference internal" href="compute_composition_atom.html">compute composition/atom command</a></li>
<li class="toctree-l2"><a class="reference internal" href="compute_contact_atom.html">compute contact/atom command</a></li>
<li class="toctree-l2"><a class="reference internal" href="compute_coord_atom.html">compute coord/atom command</a></li>
<li class="toctree-l2"><a class="reference internal" href="compute_count_type.html">compute count/type command</a></li>
<li class="toctree-l2"><a class="reference internal" href="compute_damage_atom.html">compute damage/atom command</a></li>
<li class="toctree-l2"><a class="reference internal" href="compute_dihedral.html">compute dihedral command</a></li>
<li class="toctree-l2"><a class="reference internal" href="compute_dihedral_local.html">compute dihedral/local command</a></li>
<li class="toctree-l2"><a class="reference internal" href="compute_dilatation_atom.html">compute dilatation/atom command</a></li>
<li class="toctree-l2"><a class="reference internal" href="compute_dipole.html">compute dipole command</a></li>
<li class="toctree-l2"><a class="reference internal" href="compute_dipole.html#compute-dipole-tip4p-command">compute dipole/tip4p command</a></li>
<li class="toctree-l2"><a class="reference internal" href="compute_dipole_chunk.html">compute dipole/chunk command</a></li>
<li class="toctree-l2"><a class="reference internal" href="compute_dipole_chunk.html#compute-dipole-tip4p-chunk-command">compute dipole/tip4p/chunk command</a></li>
<li class="toctree-l2"><a class="reference internal" href="compute_displace_atom.html">compute displace/atom command</a></li>
<li class="toctree-l2"><a class="reference internal" href="compute_dpd.html">compute dpd command</a></li>
<li class="toctree-l2"><a class="reference internal" href="compute_dpd_atom.html">compute dpd/atom command</a></li>
<li class="toctree-l2"><a class="reference internal" href="compute_edpd_temp_atom.html">compute edpd/temp/atom command</a></li>
<li class="toctree-l2"><a class="reference internal" href="compute_efield_atom.html">compute efield/atom command</a></li>
<li class="toctree-l2"><a class="reference internal" href="compute_efield_wolf_atom.html">compute efield/wolf/atom command</a></li>
<li class="toctree-l2"><a class="reference internal" href="compute_entropy_atom.html">compute entropy/atom command</a></li>
<li class="toctree-l2"><a class="reference internal" href="compute_erotate_asphere.html">compute erotate/asphere command</a></li>
<li class="toctree-l2"><a class="reference internal" href="compute_erotate_rigid.html">compute erotate/rigid command</a></li>
<li class="toctree-l2"><a class="reference internal" href="compute_erotate_sphere.html">compute erotate/sphere command</a></li>
<li class="toctree-l2"><a class="reference internal" href="compute_erotate_sphere_atom.html">compute erotate/sphere/atom command</a></li>
<li class="toctree-l2"><a class="reference internal" href="compute_event_displace.html">compute event/displace command</a></li>
<li class="toctree-l2"><a class="reference internal" href="compute_fabric.html">compute fabric command</a></li>
<li class="toctree-l2"><a class="reference internal" href="compute_fep.html">compute fep command</a></li>
<li class="toctree-l2"><a class="reference internal" href="compute_fep_ta.html">compute fep/ta command</a></li>
<li class="toctree-l2"><a class="reference internal" href="compute_global_atom.html">compute global/atom command</a></li>
<li class="toctree-l2"><a class="reference internal" href="compute_group_group.html">compute group/group command</a></li>
<li class="toctree-l2"><a class="reference internal" href="compute_gyration.html">compute gyration command</a></li>
<li class="toctree-l2"><a class="reference internal" href="compute_gyration_chunk.html">compute gyration/chunk command</a></li>
<li class="toctree-l2"><a class="reference internal" href="compute_gyration_shape.html">compute gyration/shape command</a></li>
<li class="toctree-l2"><a class="reference internal" href="compute_gyration_shape_chunk.html">compute gyration/shape/chunk command</a></li>
<li class="toctree-l2"><a class="reference internal" href="compute_heat_flux.html">compute heat/flux command</a></li>
<li class="toctree-l2"><a class="reference internal" href="compute_hexorder_atom.html">compute hexorder/atom command</a></li>
<li class="toctree-l2"><a class="reference internal" href="compute_hma.html">compute hma command</a></li>
<li class="toctree-l2"><a class="reference internal" href="compute_improper.html">compute improper command</a></li>
<li class="toctree-l2"><a class="reference internal" href="compute_improper_local.html">compute improper/local command</a></li>
<li class="toctree-l2"><a class="reference internal" href="compute_inertia_chunk.html">compute inertia/chunk command</a></li>
<li class="toctree-l2"><a class="reference internal" href="compute_ke.html">compute ke command</a></li>
<li class="toctree-l2"><a class="reference internal" href="compute_ke_atom.html">compute ke/atom command</a></li>
<li class="toctree-l2"><a class="reference internal" href="compute_ke_atom_eff.html">compute ke/atom/eff command</a></li>
<li class="toctree-l2"><a class="reference internal" href="compute_ke_eff.html">compute ke/eff command</a></li>
<li class="toctree-l2"><a class="reference internal" href="compute_ke_rigid.html">compute ke/rigid command</a></li>
<li class="toctree-l2"><a class="reference internal" href="compute_mliap.html">compute mliap command</a></li>
<li class="toctree-l2"><a class="reference internal" href="compute_momentum.html">compute momentum command</a></li>
<li class="toctree-l2"><a class="reference internal" href="compute_msd.html">compute msd command</a></li>
<li class="toctree-l2"><a class="reference internal" href="compute_msd_chunk.html">compute msd/chunk command</a></li>
<li class="toctree-l2"><a class="reference internal" href="compute_msd_nongauss.html">compute msd/nongauss command</a></li>
<li class="toctree-l2"><a class="reference internal" href="compute_nbond_atom.html">compute nbond/atom command</a></li>
<li class="toctree-l2"><a class="reference internal" href="compute_omega_chunk.html">compute omega/chunk command</a></li>
<li class="toctree-l2"><a class="reference internal" href="compute_orientorder_atom.html">compute orientorder/atom command</a></li>
<li class="toctree-l2"><a class="reference internal" href="compute_pace.html">compute pace command</a></li>
<li class="toctree-l2"><a class="reference internal" href="compute_pair.html">compute pair command</a></li>
<li class="toctree-l2"><a class="reference internal" href="compute_pair_local.html">compute pair/local command</a></li>
<li class="toctree-l2"><a class="reference internal" href="compute_pe.html">compute pe command</a></li>
<li class="toctree-l2"><a class="reference internal" href="compute_pe_atom.html">compute pe/atom command</a></li>
<li class="toctree-l2"><a class="reference internal" href="compute_plasticity_atom.html">compute plasticity/atom command</a></li>
<li class="toctree-l2"><a class="reference internal" href="compute_pod_atom.html">compute pod/atom command</a></li>
<li class="toctree-l2"><a class="reference internal" href="compute_pod_atom.html#compute-podd-atom-command">compute podd/atom command</a></li>
<li class="toctree-l2"><a class="reference internal" href="compute_pod_atom.html#compute-pod-local-command">compute pod/local command</a></li>
<li class="toctree-l2"><a class="reference internal" href="compute_pod_atom.html#compute-pod-global-command">compute pod/global command</a></li>
<li class="toctree-l2"><a class="reference internal" href="compute_pressure.html">compute pressure command</a></li>
<li class="toctree-l2"><a class="reference internal" href="compute_pressure_alchemy.html">compute pressure/alchemy command</a></li>
<li class="toctree-l2"><a class="reference internal" href="compute_pressure_uef.html">compute pressure/uef command</a></li>
<li class="toctree-l2"><a class="reference internal" href="compute_property_atom.html">compute property/atom command</a></li>
<li class="toctree-l2"><a class="reference internal" href="compute_property_chunk.html">compute property/chunk command</a></li>
<li class="toctree-l2"><a class="reference internal" href="compute_property_grid.html">compute property/grid command</a></li>
<li class="toctree-l2"><a class="reference internal" href="compute_property_local.html">compute property/local command</a></li>
<li class="toctree-l2"><a class="reference internal" href="compute_ptm_atom.html">compute ptm/atom command</a></li>
<li class="toctree-l2"><a class="reference internal" href="compute_rattlers_atom.html">compute rattlers/atom command</a></li>
<li class="toctree-l2"><a class="reference internal" href="compute_rdf.html">compute rdf command</a></li>
<li class="toctree-l2"><a class="reference internal" href="compute_reaxff_atom.html">compute reaxff/atom command</a></li>
<li class="toctree-l2"><a class="reference internal" href="compute_reduce.html">compute reduce command</a></li>
<li class="toctree-l2"><a class="reference internal" href="compute_reduce.html#compute-reduce-region-command">compute reduce/region command</a></li>
<li class="toctree-l2"><a class="reference internal" href="compute_reduce_chunk.html">compute reduce/chunk command</a></li>
<li class="toctree-l2"><a class="reference internal" href="compute_rheo_property_atom.html">compute rheo/property/atom command</a></li>
<li class="toctree-l2"><a class="reference internal" href="compute_rigid_local.html">compute rigid/local command</a></li>
<li class="toctree-l2"><a class="reference internal" href="compute_saed.html">compute saed command</a></li>
<li class="toctree-l2"><a class="reference internal" href="compute_slcsa_atom.html">compute slcsa/atom command</a></li>
<li class="toctree-l2"><a class="reference internal" href="compute_slice.html">compute slice command</a></li>
<li class="toctree-l2"><a class="reference internal" href="compute_smd_contact_radius.html">compute smd/contact/radius command</a></li>
<li class="toctree-l2"><a class="reference internal" href="compute_smd_damage.html">compute smd/damage command</a></li>
<li class="toctree-l2"><a class="reference internal" href="compute_smd_hourglass_error.html">compute smd/hourglass/error command</a></li>
<li class="toctree-l2"><a class="reference internal" href="compute_smd_internal_energy.html">compute smd/internal/energy command</a></li>
<li class="toctree-l2"><a class="reference internal" href="compute_smd_plastic_strain.html">compute smd/plastic/strain command</a></li>
<li class="toctree-l2"><a class="reference internal" href="compute_smd_plastic_strain_rate.html">compute smd/plastic/strain/rate command</a></li>
<li class="toctree-l2"><a class="reference internal" href="compute_smd_rho.html">compute smd/rho command</a></li>
<li class="toctree-l2"><a class="reference internal" href="compute_smd_tlsph_defgrad.html">compute smd/tlsph/defgrad command</a></li>
<li class="toctree-l2"><a class="reference internal" href="compute_smd_tlsph_dt.html">compute smd/tlsph/dt command</a></li>
<li class="toctree-l2"><a class="reference internal" href="compute_smd_tlsph_num_neighs.html">compute smd/tlsph/num/neighs command</a></li>
<li class="toctree-l2"><a class="reference internal" href="compute_smd_tlsph_shape.html">compute smd/tlsph/shape command</a></li>
<li class="toctree-l2"><a class="reference internal" href="compute_smd_tlsph_strain.html">compute smd/tlsph/strain command</a></li>
<li class="toctree-l2"><a class="reference internal" href="compute_smd_tlsph_strain_rate.html">compute smd/tlsph/strain/rate command</a></li>
<li class="toctree-l2"><a class="reference internal" href="compute_smd_tlsph_stress.html">compute smd/tlsph/stress command</a></li>
<li class="toctree-l2"><a class="reference internal" href="compute_smd_triangle_vertices.html">compute smd/triangle/vertices command</a></li>
<li class="toctree-l2"><a class="reference internal" href="compute_smd_ulsph_effm.html">compute smd/ulsph/effm command</a></li>
<li class="toctree-l2"><a class="reference internal" href="compute_smd_ulsph_num_neighs.html">compute smd/ulsph/num/neighs command</a></li>
<li class="toctree-l2"><a class="reference internal" href="compute_smd_ulsph_strain.html">compute smd/ulsph/strain command</a></li>
<li class="toctree-l2"><a class="reference internal" href="compute_smd_ulsph_strain_rate.html">compute smd/ulsph/strain/rate command</a></li>
<li class="toctree-l2"><a class="reference internal" href="compute_smd_ulsph_stress.html">compute smd/ulsph/stress command</a></li>
<li class="toctree-l2"><a class="reference internal" href="compute_smd_vol.html">compute smd/vol command</a></li>
<li class="toctree-l2"><a class="reference internal" href="compute_sna_atom.html">compute sna/atom command</a></li>
<li class="toctree-l2"><a class="reference internal" href="compute_sna_atom.html#compute-snad-atom-command">compute snad/atom command</a></li>
<li class="toctree-l2"><a class="reference internal" href="compute_sna_atom.html#compute-snav-atom-command">compute snav/atom command</a></li>
<li class="toctree-l2"><a class="reference internal" href="compute_sna_atom.html#compute-snap-command">compute snap command</a></li>
<li class="toctree-l2"><a class="reference internal" href="compute_sna_atom.html#compute-sna-grid-command">compute sna/grid command</a></li>
<li class="toctree-l2"><a class="reference internal" href="compute_sna_atom.html#compute-sna-grid-local-command">compute sna/grid/local command</a></li>
<li class="toctree-l2"><a class="reference internal" href="compute_sph_e_atom.html">compute sph/e/atom command</a></li>
<li class="toctree-l2"><a class="reference internal" href="compute_sph_rho_atom.html">compute sph/rho/atom command</a></li>
<li class="toctree-l2"><a class="reference internal" href="compute_sph_t_atom.html">compute sph/t/atom command</a></li>
<li class="toctree-l2"><a class="reference internal" href="compute_spin.html">compute spin command</a></li>
<li class="toctree-l2"><a class="reference internal" href="compute_stress_atom.html">compute stress/atom command</a></li>
<li class="toctree-l2"><a class="reference internal" href="compute_stress_atom.html#compute-centroid-stress-atom-command">compute centroid/stress/atom command</a></li>
<li class="toctree-l2"><a class="reference internal" href="compute_stress_cartesian.html">compute stress/cartesian command</a></li>
<li class="toctree-l2"><a class="reference internal" href="compute_stress_curvilinear.html">compute stress/cylinder command</a></li>
<li class="toctree-l2"><a class="reference internal" href="compute_stress_curvilinear.html#compute-stress-spherical-command">compute stress/spherical command</a></li>
<li class="toctree-l2"><a class="reference internal" href="compute_stress_mop.html">compute stress/mop command</a></li>
<li class="toctree-l2"><a class="reference internal" href="compute_stress_mop.html#compute-stress-mop-profile-command">compute stress/mop/profile command</a></li>
<li class="toctree-l2"><a class="reference internal" href="compute_tally.html">compute force/tally command</a></li>
<li class="toctree-l2"><a class="reference internal" href="compute_tally.html#compute-heat-flux-tally-command">compute heat/flux/tally command</a></li>
<li class="toctree-l2"><a class="reference internal" href="compute_tally.html#compute-heat-flux-virial-tally-command">compute heat/flux/virial/tally command</a></li>
<li class="toctree-l2"><a class="reference internal" href="compute_tally.html#compute-pe-tally-command">compute pe/tally command</a></li>
<li class="toctree-l2"><a class="reference internal" href="compute_tally.html#compute-pe-mol-tally-command">compute pe/mol/tally command</a></li>
<li class="toctree-l2"><a class="reference internal" href="compute_tally.html#compute-stress-tally-command">compute stress/tally command</a></li>
<li class="toctree-l2"><a class="reference internal" href="compute_tdpd_cc_atom.html">compute tdpd/cc/atom command</a></li>
<li class="toctree-l2"><a class="reference internal" href="compute_temp.html">compute temp command</a></li>
<li class="toctree-l2"><a class="reference internal" href="compute_temp_asphere.html">compute temp/asphere command</a></li>
<li class="toctree-l2"><a class="reference internal" href="compute_temp_body.html">compute temp/body command</a></li>
<li class="toctree-l2"><a class="reference internal" href="compute_temp_chunk.html">compute temp/chunk command</a></li>
<li class="toctree-l2"><a class="reference internal" href="compute_temp_com.html">compute temp/com command</a></li>
<li class="toctree-l2"><a class="reference internal" href="compute_temp_cs.html">compute temp/cs command</a></li>
<li class="toctree-l2"><a class="reference internal" href="compute_temp_deform.html">compute temp/deform command</a></li>
<li class="toctree-l2"><a class="reference internal" href="compute_temp_deform_eff.html">compute temp/deform/eff command</a></li>
<li class="toctree-l2"><a class="reference internal" href="compute_temp_drude.html">compute temp/drude command</a></li>
<li class="toctree-l2"><a class="reference internal" href="compute_temp_eff.html">compute temp/eff command</a></li>
<li class="toctree-l2"><a class="reference internal" href="compute_temp_partial.html">compute temp/partial command</a></li>
<li class="toctree-l2"><a class="reference internal" href="compute_temp_profile.html">compute temp/profile command</a></li>
<li class="toctree-l2"><a class="reference internal" href="compute_temp_ramp.html">compute temp/ramp command</a></li>
<li class="toctree-l2"><a class="reference internal" href="compute_temp_region.html">compute temp/region command</a></li>
<li class="toctree-l2"><a class="reference internal" href="compute_temp_region_eff.html">compute temp/region/eff command</a></li>
<li class="toctree-l2"><a class="reference internal" href="compute_temp_rotate.html">compute temp/rotate command</a></li>
<li class="toctree-l2"><a class="reference internal" href="compute_temp_sphere.html">compute temp/sphere command</a></li>
<li class="toctree-l2"><a class="reference internal" href="compute_temp_uef.html">compute temp/uef command</a></li>
<li class="toctree-l2"><a class="reference internal" href="compute_ti.html">compute ti command</a></li>
<li class="toctree-l2"><a class="reference internal" href="compute_torque_chunk.html">compute torque/chunk command</a></li>
<li class="toctree-l2"><a class="reference internal" href="compute_vacf.html">compute vacf command</a></li>
<li class="toctree-l2"><a class="reference internal" href="compute_vcm_chunk.html">compute vcm/chunk command</a></li>
<li class="toctree-l2"><a class="reference internal" href="compute_viscosity_cos.html">compute viscosity/cos command</a></li>
<li class="toctree-l2"><a class="reference internal" href="compute_voronoi_atom.html">compute voronoi/atom command</a></li>
<li class="toctree-l2"><a class="reference internal" href="compute_xrd.html">compute xrd command</a></li>
</ul>
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<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>
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<li class="toctree-l1"><a class="reference internal" href="dihedrals.html">Dihedral Styles</a></li>
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<p><span class="math notranslate nohighlight">\(\renewcommand{\AA}{\text{Å}}\)</span></p>
<section id="compute-centro-atom-command">
<span id="index-0"></span><h1>compute centro/atom command<a class="headerlink" href="#compute-centro-atom-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">compute </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">centro</span><span class="o">/</span><span class="n">atom</span><span class="w"> </span><span class="n">lattice</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>
<li><p>ID, group-ID are documented in <a class="reference internal" href="compute.html"><span class="doc">compute</span></a> command</p></li>
<li><p>centro/atom = style name of this compute command</p></li>
<li><p>lattice = <em>fcc</em> or <em>bcc</em> or N = # of neighbors per atom to include</p></li>
<li><p>zero or more keyword/value pairs may be appended</p></li>
<li><p>keyword = <em>axes</em></p>
<pre class="literal-block"><em>axes</em> value = <em>no</em> or <em>yes</em>
<em>no</em> = do not calculate 3 symmetry axes
<em>yes</em> = calculate 3 symmetry axes</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">compute </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">centro</span><span class="o">/</span><span class="n">atom</span><span class="w"> </span><span class="n">fcc</span>
<span class="k">compute </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">centro</span><span class="o">/</span><span class="n">atom</span><span class="w"> </span><span class="m">8</span>
</pre></div>
</div>
</section>
<section id="description">
<h2>Description<a class="headerlink" href="#description" title="Link to this heading"></a></h2>
<p>Define a computation that calculates the centro-symmetry parameter for
each atom in the group, for either FCC or BCC lattices, depending on
the choice of the <em>lattice</em> argument. In solid-state systems the
centro-symmetry parameter is a useful measure of the local lattice
disorder around an atom and can be used to characterize whether the
atom is part of a perfect lattice, a local defect (e.g. a dislocation
or stacking fault), or at a surface.</p>
<p>The value of the centro-symmetry parameter will be 0.0 for atoms not
in the specified compute group.</p>
<p>This parameter is computed using the following formula from
<a class="reference internal" href="#kelchner"><span class="std std-ref">(Kelchner)</span></a></p>
<div class="math notranslate nohighlight">
\[CS = \sum_{i = 1}^{N/2} | \vec{R}_i + \vec{R}_{i+N/2} |^2\]</div>
<p>where the <span class="math notranslate nohighlight">\(N\)</span> nearest neighbors of each atom are identified and
<span class="math notranslate nohighlight">\(\vec{R}_i\)</span> and <span class="math notranslate nohighlight">\(\vec{R}_{i+N/2}\)</span> are vectors from the
central atom to a particular pair of nearest neighbors. There are
<span class="math notranslate nohighlight">\(N (N-1)/2\)</span> possible neighbor pairs that can contribute to this
formula. The quantity in the sum is computed for each, and the
<span class="math notranslate nohighlight">\(N/2\)</span> smallest are used. This will typically be for pairs of
atoms in symmetrically opposite positions with respect to the central
atom; hence the <span class="math notranslate nohighlight">\(i+N/2\)</span> notation.</p>
<p><span class="math notranslate nohighlight">\(N\)</span> is an input parameter, which should be set to correspond to
the number of nearest neighbors in the underlying lattice of atoms.
If the keyword <em>fcc</em> or <em>bcc</em> is used, <em>N</em> is set to 12 and 8
respectively. More generally, <em>N</em> can be set to a positive, even
integer.</p>
<p>For an atom on a lattice site, surrounded by atoms on a perfect
lattice, the centro-symmetry parameter will be 0. It will be near 0
for small thermal perturbations of a perfect lattice. If a point
defect exists, the symmetry is broken, and the parameter will be a
larger positive value. An atom at a surface will have a large
positive parameter. If the atom does not have <span class="math notranslate nohighlight">\(N\)</span> neighbors
(within the potential cutoff), then its centro-symmetry parameter is
set to 0.0.</p>
<p>If the keyword <em>axes</em> has the setting <em>yes</em>, then this compute also
estimates three symmetry axes for each atoms local neighborhood. The
first two of these are the vectors joining the two pairs of neighbor
atoms with smallest contributions to the centrosymmetry parameter,
i.e. the two most symmetric pairs of atoms. The third vector is
normal to the first two by the right-hand rule. All three vectors are
normalized to unit length. For FCC crystals, the first two vectors
will lie along a <span class="math notranslate nohighlight">\(\langle110\rangle\)</span> direction, while the third vector
will lie along either a <span class="math notranslate nohighlight">\(\langle100\rangle\)</span> or <span class="math notranslate nohighlight">\(\langle111\rangle\)</span>
direction. For HCP crystals, the first two vectors will lie along
<span class="math notranslate nohighlight">\(\langle1000\rangle\)</span> directions, while the third vector
will lie along <span class="math notranslate nohighlight">\(\langle0001\rangle\)</span>. This provides a simple way to
measure local orientation in HCP structures. In general, the <em>axes</em> keyword
can be used to estimate the orientation of symmetry axes in the neighborhood
of any atom.</p>
<p>Only atoms within the cutoff of the pairwise neighbor list are
considered as possible neighbors. Atoms not in the compute group are
included in the <span class="math notranslate nohighlight">\(N\)</span> neighbors used in this calculation.</p>
<p>The neighbor list needed to compute this quantity is constructed each
time the calculation is performed (e.g., each time a snapshot of atoms
is dumped). Thus it can be inefficient to compute/dump this quantity
too frequently or to have multiple compute/dump commands, each with a
<em>centro/atom</em> style.</p>
</section>
<section id="output-info">
<h2>Output info<a class="headerlink" href="#output-info" title="Link to this heading"></a></h2>
<p>By default, this compute calculates the centrosymmetry value for each
atom as a per-atom vector, which can be accessed by any command that
uses per-atom values from a compute as input. See the <a class="reference internal" href="Howto_output.html"><span class="doc">Howto output</span></a> page for an overview of LAMMPS output
options.</p>
<p>If the <em>axes</em> keyword setting is <em>yes</em>, then a per-atom array is
calculated. The first column is the centrosymmetry parameter. The
next three columns are the <em>x</em>, <em>y</em>, and <em>z</em> components of the first
symmetry axis, followed by the second, and third symmetry axes in
columns 57 and 810.</p>
<p>The centrosymmetry values are unitless values <span class="math notranslate nohighlight">\(\ge 0.0\)</span>. Their magnitude
depends on the lattice style due to the number of contributing neighbor
pairs in the summation in the formula above. And it depends on the
local defects surrounding the central atom, as described above. For
the <em>axes yes</em> case, the vector components are also unitless, since
they represent spatial directions.</p>
<p>Here are typical centro-symmetry values, from a nanoindentation
simulation into gold (FCC). These were provided by Jon Zimmerman
(Sandia):</p>
<div class="highlight-none notranslate"><div class="highlight"><pre><span></span>Bulk lattice = 0
Dislocation core ~ 1.0 (0.5 to 1.25)
Stacking faults ~ 5.0 (4.0 to 6.0)
Free surface ~ 23.0
</pre></div>
</div>
<p>These values are <strong>not</strong> normalized by the square of the lattice
parameter. If they were, normalized values would be:</p>
<div class="highlight-none notranslate"><div class="highlight"><pre><span></span>Bulk lattice = 0
Dislocation core ~ 0.06 (0.03 to 0.075)
Stacking faults ~ 0.3 (0.24 to 0.36)
Free surface ~ 1.38
</pre></div>
</div>
<p>For BCC materials, the values for dislocation cores and free surfaces
would be somewhat different, due to their being only 8 neighbors instead
of 12.</p>
</section>
<section id="restrictions">
<h2>Restrictions<a class="headerlink" href="#restrictions" title="Link to this heading"></a></h2>
<blockquote>
<div><p>none</p>
</div></blockquote>
</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="compute_cna_atom.html"><span class="doc">compute cna/atom</span></a></p>
</section>
<section id="default">
<h2>Default<a class="headerlink" href="#default" title="Link to this heading"></a></h2>
<p>The default value for the optional keyword is axes = no.</p>
<hr class="docutils" />
<p id="kelchner"><strong>(Kelchner)</strong> Kelchner, Plimpton, Hamilton, Phys Rev B, 58, 11085 (1998).</p>
</section>
</section>
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