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explain that the computed force in python pair is force/r same as in Pair:single()

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Axel Kohlmeyer
2022-01-03 10:12:38 -05:00
parent 882e699163
commit bc5d742623
2 changed files with 28 additions and 28 deletions
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38
doc/src/Modify_pair.rst
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@ -12,24 +12,24 @@ includes some optional methods to enable its use with rRESPA.
Here is a brief description of the class methods in pair.h:
+---------------------------------+-------------------------------------------------------------------+
| compute | workhorse routine that computes pairwise interactions |
+---------------------------------+-------------------------------------------------------------------+
| settings | reads the input script line with arguments you define |
+---------------------------------+-------------------------------------------------------------------+
| coeff | set coefficients for one i,j type pair |
+---------------------------------+-------------------------------------------------------------------+
| init_one | perform initialization for one i,j type pair |
+---------------------------------+-------------------------------------------------------------------+
| init_style | initialization specific to this pair style |
+---------------------------------+-------------------------------------------------------------------+
| write & read_restart | write/read i,j pair coeffs to restart files |
+---------------------------------+-------------------------------------------------------------------+
| write & read_restart_settings | write/read global settings to restart files |
+---------------------------------+-------------------------------------------------------------------+
| single | force and energy of a single pairwise interaction between 2 atoms |
+---------------------------------+-------------------------------------------------------------------+
| compute_inner/middle/outer | versions of compute used by rRESPA |
+---------------------------------+-------------------------------------------------------------------+
+---------------------------------+---------------------------------------------------------------------+
| compute | workhorse routine that computes pairwise interactions |
+---------------------------------+---------------------------------------------------------------------+
| settings | reads the input script line with arguments you define |
+---------------------------------+---------------------------------------------------------------------+
| coeff | set coefficients for one i,j type pair |
+---------------------------------+---------------------------------------------------------------------+
| init_one | perform initialization for one i,j type pair |
+---------------------------------+---------------------------------------------------------------------+
| init_style | initialization specific to this pair style |
+---------------------------------+---------------------------------------------------------------------+
| write & read_restart | write/read i,j pair coeffs to restart files |
+---------------------------------+---------------------------------------------------------------------+
| write & read_restart_settings | write/read global settings to restart files |
+---------------------------------+---------------------------------------------------------------------+
| single | force/r and energy of a single pairwise interaction between 2 atoms |
+---------------------------------+---------------------------------------------------------------------+
| compute_inner/middle/outer | versions of compute used by rRESPA |
+---------------------------------+---------------------------------------------------------------------+
The inner/middle/outer routines are optional.

18
doc/src/pair_python.rst
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@ -126,11 +126,11 @@ and *compute_energy*, which both take 3 numerical arguments:
* itype = the (numerical) type of the first atom
* jtype = the (numerical) type of the second atom
This functions need to compute the force and the energy, respectively,
and use the result as return value. The functions need to use the
*pmap* dictionary to convert the LAMMPS atom type number to the symbolic
value of the internal potential parameter data structure. Following
the *LJCutMelt* example, here are the two functions:
This functions need to compute the (scaled) force and the energy,
respectively, and use the result as return value. The functions need
to use the *pmap* dictionary to convert the LAMMPS atom type number
to the symbolic value of the internal potential parameter data structure.
Following the *LJCutMelt* example, here are the two functions:
.. code-block:: python
@ -154,10 +154,10 @@ the *LJCutMelt* example, here are the two functions:
for consistency with the C++ pair styles in LAMMPS, the
*compute_force* function follows the conventions of the Pair::single()
methods and does not return the full force, but the force scaled by
the distance between the two atoms, so this value only needs to be
multiplied by delta x, delta y, and delta z to conveniently obtain the
three components of the force vector between these two atoms.
methods and does not return the pairwise force directly, but the force
divided by the distance between the two atoms, so this value only needs
to be multiplied by delta x, delta y, and delta z to conveniently obtain
the three components of the force vector between these two atoms.
----------