75 lines
2.7 KiB
ReStructuredText
75 lines
2.7 KiB
ReStructuredText
.. index:: fix_modify AtC gradients
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fix_modify AtC gradients command
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================================
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Syntax
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""""""
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.. parsed-literal::
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fix_modify <AtC fixID> gradients <add|delete> <list_of_fields>
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* AtC fixID = ID of :doc:`fix atc <fix_atc>` instance
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* gradients = name of the AtC sub-command
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* *add* or *delete* = select whether to add or delete calculation of gradients for the listed output fields
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* list_of_fields = one or more of the fields listed below:
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- density : mass per unit volume
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- displacement : displacement vector
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- momentum : momentum per unit volume
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- velocity : defined by momentum divided by density
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- projected_velocity : simple kernel estimation of atomic velocities
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- temperature : temperature derived from the relative atomic kinetic energy
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- kinetic_temperature : temperature derived from the full kinetic energy
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- number_density : simple kernel estimation of number of atoms per unit volume
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- stress : Cauchy stress tensor for eulerian analysis (atom_element_map), or first Piola-Kirchhoff stress tensor for lagrangian analysis
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- transformed_stress : first Piola-Kirchhoff stress tensor for eulerian analysis (atom_element_map), or Cauchy stress tensor for lagrangian analysis
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- heat_flux : spatial heat flux vector for eulerian, or referential heat flux vector for lagrangian
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- potential_energy : potential energy per unit volume
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- kinetic_energy : kinetic energy per unit volume
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- thermal_energy : thermal energy (kinetic energy - continuum kinetic energy) per unit volume
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- internal_energy : total internal energy (potential + thermal) per unit volume
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- energy : total energy (potential + kinetic) per unit volume
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- number_density : number of atoms per unit volume
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- eshelby_stress : configurational stress (energy-momentum) tensor defined by [Eshelby]_
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- vacancy_concentration : volume fraction of vacancy content
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- type_concentration : volume fraction of a specific atom type
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Examples
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""""""""
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.. code-block:: LAMMPS
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fix_modify AtC gradients add temperature velocity stress
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fix_modify AtC gradients delete velocity
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Description
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"""""""""""
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Requests calculation and output of gradients of the fields from the AtC
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transfer class. These gradients will be with regard to spatial or
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material coordinate for Eulerian or Lagrangian analysis, respectively,
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as specified by :doc:`fix_modify AtC atom_element_map <atc_atom_element_map>`
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Restrictions
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""""""""""""
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Must be used with :doc:`fix atc hardy <fix_atc>`.
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Related AtC commands
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""""""""""""""""""""
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- :ref:`fix_modify AtC command overview <atc_fix_modify>`
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- :doc:`fix_modify AtC atom_element_map <atc_atom_element_map>`
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- :doc:`fix_modify AtC fields <atc_hardy_fields>`
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- :doc:`fix_modify AtC rates <atc_hardy_rates>`
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Default
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"""""""
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None.
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