forked from lijiext/lammps
102 lines
2.4 KiB
Plaintext
102 lines
2.4 KiB
Plaintext
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.. index:: bond_style class2
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bond_style class2 command
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=========================
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bond_style class2/omp command
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=============================
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Syntax
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""""""
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.. parsed-literal::
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bond_style class2
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Examples
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""""""""
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.. parsed-literal::
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bond_style class2
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bond_coeff 1 1.0 100.0 80.0 80.0
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Description
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"""""""""""
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The *class2* bond style uses the potential
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.. image:: Eqs/bond_class2.jpg
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:align: center
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where r0 is the equilibrium bond distance.
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See :ref:`(Sun) <Sun>` for a description of the COMPASS class2 force field.
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The following coefficients must be defined for each bond type via the
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:doc:`bond_coeff <bond_coeff>` command as in the example above, or in
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the data file or restart files read by the :doc:`read_data <read_data>`
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or :doc:`read_restart <read_restart>` commands:
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* R0 (distance)
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* K2 (energy/distance^2)
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* K3 (energy/distance^3)
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* K4 (energy/distance^4)
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----------
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Styles with a *cuda*, *gpu*, *intel*, *kk*, *omp*, or *opt* suffix are
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functionally the same as the corresponding style without the suffix.
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They have been optimized to run faster, depending on your available
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hardware, as discussed in :doc:`Section_accelerate <Section_accelerate>`
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of the manual. The accelerated styles take the same arguments and
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should produce the same results, except for round-off and precision
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issues.
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These accelerated styles are part of the USER-CUDA, GPU, USER-INTEL,
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KOKKOS, USER-OMP and OPT packages, respectively. They are only
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enabled if LAMMPS was built with those packages. See the :ref:`Making LAMMPS <start_3>` section for more info.
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You can specify the accelerated styles explicitly in your input script
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by including their suffix, or you can use the :ref:`-suffix command-line switch <start_7>` when you invoke LAMMPS, or you can
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use the :doc:`suffix <suffix>` command in your input script.
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See :doc:`Section_accelerate <Section_accelerate>` of the manual for
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more instructions on how to use the accelerated styles effectively.
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----------
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Restrictions
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""""""""""""
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This bond style can only be used if LAMMPS was built with the CLASS2
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package. See the :ref:`Making LAMMPS <start_3>` section
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for more info on packages.
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Related commands
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""""""""""""""""
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:doc:`bond_coeff <bond_coeff>`, :doc:`delete_bonds <delete_bonds>`
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**Default:** none
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----------
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.. _Sun:
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**(Sun)** Sun, J Phys Chem B 102, 7338-7364 (1998).
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.. _lws: http://lammps.sandia.gov
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.. _ld: Manual.html
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.. _lc: Section_commands.html#comm
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