fix_modify AtC rates command


fix_modify <AtC fixID> rates <add|delete> <list_of_fields>
  • AtC fixID = ID of fix atc instance

  • rates = name of the AtC sub-command

  • add or delete = select whether to add or delete calculation of rates for the listed output fields

  • list_of_fields = one or more of the fields listed below:

    • density : mass per unit volume

    • displacement : displacement vector

    • momentum : momentum per unit volume

    • velocity : defined by momentum divided by density

    • projected_velocity : simple kernel estimation of atomic velocities

    • temperature : temperature derived from the relative atomic kinetic energy

    • kinetic_temperature : temperature derived from the full kinetic energy

    • number_density : simple kernel estimation of number of atoms per unit volume

    • stress : Cauchy stress tensor for eulerian analysis (atom_element_map), or first Piola-Kirchhoff stress tensor for lagrangian analysis

    • transformed_stress : first Piola-Kirchhoff stress tensor for eulerian analysis (atom_element_map), or Cauchy stress tensor for lagrangian analysis

    • heat_flux : spatial heat flux vector for eulerian, or referential heat flux vector for lagrangian

    • potential_energy : potential energy per unit volume

    • kinetic_energy : kinetic energy per unit volume

    • thermal_energy : thermal energy (kinetic energy - continuum kinetic energy) per unit volume

    • internal_energy : total internal energy (potential + thermal) per unit volume

    • energy : total energy (potential + kinetic) per unit volume

    • number_density : number of atoms per unit volume

    • eshelby_stress : configurational stress (energy-momentum) tensor defined by [Eshelby]

    • vacancy_concentration : volume fraction of vacancy content

    • type_concentration : volume fraction of a specific atom type


fix_modify AtC rates add temperature velocity stress
fix_modify AtC rates delete stress


Requests calculation and output of rates (time derivatives) of the fields from the AtC transfer class. For Eulerian analysis (see fix_modify AtC atom_element_map) these rates are the partial time derivatives of the nodal fields, not the full (material) time derivatives.


Must be used with fix atc hardy.