58 lines
4.1 KiB
ReStructuredText
58 lines
4.1 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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| 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 USER-TALLY package
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provides *examples*\ \_compute\_tally.html for utilizing this mechanism.
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