b016b135fa
This way individual computes can add custom keywords to compute_modify in a similar fashion as fixes
60 lines
4.2 KiB
ReStructuredText
60 lines
4.2 KiB
ReStructuredText
Compute styles
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==============
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Classes that compute scalar and vector quantities like temperature
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and the pressure tensor, as well as classes that compute per-atom
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quantities like kinetic energy and the centro-symmetry parameter
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are derived from the Compute class. New styles can be created
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to add new calculations to LAMMPS.
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Compute_temp.cpp is a simple example of computing a scalar
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temperature. Compute_ke_atom.cpp is a simple example of computing
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per-atom kinetic energy.
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Here is a brief description of methods you define in your new derived
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class. See compute.h for details.
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+-----------------------+------------------------------------------------------------------+
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| init | perform one time setup (required) |
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+-----------------------+------------------------------------------------------------------+
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| init_list | neighbor list setup, if needed (optional) |
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+-----------------------+------------------------------------------------------------------+
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| compute_scalar | compute a scalar quantity (optional) |
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+-----------------------+------------------------------------------------------------------+
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| compute_vector | compute a vector of quantities (optional) |
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+-----------------------+------------------------------------------------------------------+
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| compute_peratom | compute one or more quantities per atom (optional) |
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+-----------------------+------------------------------------------------------------------+
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| compute_local | compute one or more quantities per processor (optional) |
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+-----------------------+------------------------------------------------------------------+
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| pack_comm | pack a buffer with items to communicate (optional) |
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+-----------------------+------------------------------------------------------------------+
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| unpack_comm | unpack the buffer (optional) |
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+-----------------------+------------------------------------------------------------------+
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| pack_reverse | pack a buffer with items to reverse communicate (optional) |
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+-----------------------+------------------------------------------------------------------+
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| unpack_reverse | unpack the buffer (optional) |
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+-----------------------+------------------------------------------------------------------+
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| remove_bias | remove velocity bias from one atom (optional) |
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+-----------------------+------------------------------------------------------------------+
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| remove_bias_all | remove velocity bias from all atoms in group (optional) |
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+-----------------------+------------------------------------------------------------------+
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| restore_bias | restore velocity bias for one atom after remove_bias (optional) |
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+-----------------------+------------------------------------------------------------------+
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| restore_bias_all | same as before, but for all atoms in group (optional) |
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+-----------------------+------------------------------------------------------------------+
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| pair_tally_callback | callback function for *tally*\ -style computes (optional). |
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+-----------------------+------------------------------------------------------------------+
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| modify_param | called when a compute_modify request is executed (optional) |
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+-----------------------+------------------------------------------------------------------+
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| memory_usage | tally memory usage (optional) |
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+-----------------------+------------------------------------------------------------------+
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Tally-style computes are a special case, as their computation is done
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in two stages: the callback function is registered with the pair style
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and then called from the Pair::ev_tally() function, which is called for
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each pair after force and energy has been computed for this pair. Then
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the tallied values are retrieved with the standard compute_scalar or
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compute_vector or compute_peratom methods. The :doc:`compute styles in the TALLY package <compute_tally>`
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provide *examples* for utilizing this mechanism.
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