From 6839caaba7966f9ba4480bc3f7a799872f65db43 Mon Sep 17 00:00:00 2001 From: sjplimp Date: Thu, 31 Jan 2013 18:15:52 +0000 Subject: [PATCH] git-svn-id: svn://svn.icms.temple.edu/lammps-ro/trunk@9355 f3b2605a-c512-4ea7-a41b-209d697bcdaa --- doc/pair_body.html | 45 +++++++++++++++++++++++++-------------------- doc/pair_body.txt | 45 +++++++++++++++++++++++++-------------------- 2 files changed, 50 insertions(+), 40 deletions(-) diff --git a/doc/pair_body.html b/doc/pair_body.html index 0973ea5bcf..686b575187 100644 --- a/doc/pair_body.html +++ b/doc/pair_body.html @@ -25,24 +25,26 @@ pair_coeff 1 1 1.0 1.5 2.5

Description:

-

Style body treats particles which are body particles and computes -pairwise body/body interaction as well as interactions between body -and point-particles. See Section_howto 22 of the +

Style body is for use with body particles and calculates pairwise +body/body interactions as well as interactions between body and +point-particles. See Section_howto 22 of the manual for an overview of using body particles.

This pair style is designed for use with the "nparticle" body style, which is specified as an argument to the "atom-style body" command. -See the body doc page for more details about all the body -styles LAMMPS supports. The nparticle style treats a body particle as -a rigid body composed of N sub-particles. +See the body doc page for more details about the body +styles LAMMPS supports. The "nparticle" style treats a body particle +as a rigid body composed of N sub-particles.

-

The position of a body particle is the position of its center-of-mass -(COM). If the COMs of a pair of body particles are within the cutoff -(global or type-specific, as specified above), then all interactions -between pairs of sub-particles in the two body particles are computed. +

The coordinates of a body particle are its center-of-mass (COM). If +the COMs of a pair of body particles are within the cutoff (global or +type-specific, as specified above), then all interactions between +pairs of sub-particles in the two body particles are computed. E.g. if the first body particle has 3 sub-particles, and the second -has 10, then 30 interactions are computed to sum the total force and -torque on each body particle. Note that all 30 interactions are +has 10, then 30 interactions are computed and summed to yield the +total force and torque on each body particle. +

+

IMPORTANT NOTE: In the example just described, all 30 interactions are computed even if the distance between a particular pair of sub-particles is greater than the cutoff. Likewise, no interaction between two body particles is computed if the two COMs are further @@ -55,15 +57,18 @@ shape and size. particle. The distance between the two particles is calculated using the COM of the body particle and the position of the point particle. If the distance is within the cutoff and the body particle has N -sub-particles, then N interactions are computed with the point -particle. If the distance is not within the cutoff, no interactions -between the body and point particle are computed. +sub-particles, then N interactions with the point particle are +computed and summed. If the distance is not within the cutoff, no +interactions between the body and point particle are computed.

-

The interaction between two sub-particles (or a sub-particle and point -particle) is computed as a Lennard-Jones interaction, using the -standard formula on the pair_style lj/cut doc page. -The espilon and sigma values are based on the atom type of the parent -body particle. +

The interaction between two sub-particles, or a sub-particle and point +particle, or betwee two point particles is computed as a Lennard-Jones +interaction, using the standard formula +

+
+
+

where Rc is the cutoff. As explained above, an interaction involving +one or two body sub-particles may be computed even for r > Rc.

For style body, the following coefficients must be defined for each pair of atoms types via the pair_coeff command as in diff --git a/doc/pair_body.txt b/doc/pair_body.txt index 794c3e0dc5..4fbeef2c1b 100644 --- a/doc/pair_body.txt +++ b/doc/pair_body.txt @@ -22,24 +22,26 @@ pair_coeff 1 1 1.0 1.5 2.5 :pre [Description:] -Style {body} treats particles which are body particles and computes -pairwise body/body interaction as well as interactions between body -and point-particles. See "Section_howto 22"_Section_howto.html of the +Style {body} is for use with body particles and calculates pairwise +body/body interactions as well as interactions between body and +point-particles. See "Section_howto 22"_Section_howto.html of the manual for an overview of using body particles. This pair style is designed for use with the "nparticle" body style, which is specified as an argument to the "atom-style body" command. -See the "body"_body.html doc page for more details about all the body -styles LAMMPS supports. The nparticle style treats a body particle as -a rigid body composed of N sub-particles. +See the "body"_body.html doc page for more details about the body +styles LAMMPS supports. The "nparticle" style treats a body particle +as a rigid body composed of N sub-particles. -The position of a body particle is the position of its center-of-mass -(COM). If the COMs of a pair of body particles are within the cutoff -(global or type-specific, as specified above), then all interactions -between pairs of sub-particles in the two body particles are computed. +The coordinates of a body particle are its center-of-mass (COM). If +the COMs of a pair of body particles are within the cutoff (global or +type-specific, as specified above), then all interactions between +pairs of sub-particles in the two body particles are computed. E.g. if the first body particle has 3 sub-particles, and the second -has 10, then 30 interactions are computed to sum the total force and -torque on each body particle. Note that all 30 interactions are +has 10, then 30 interactions are computed and summed to yield the +total force and torque on each body particle. + +IMPORTANT NOTE: In the example just described, all 30 interactions are computed even if the distance between a particular pair of sub-particles is greater than the cutoff. Likewise, no interaction between two body particles is computed if the two COMs are further @@ -52,15 +54,18 @@ Similar rules apply for a body particle interacting with a point particle. The distance between the two particles is calculated using the COM of the body particle and the position of the point particle. If the distance is within the cutoff and the body particle has N -sub-particles, then N interactions are computed with the point -particle. If the distance is not within the cutoff, no interactions -between the body and point particle are computed. +sub-particles, then N interactions with the point particle are +computed and summed. If the distance is not within the cutoff, no +interactions between the body and point particle are computed. -The interaction between two sub-particles (or a sub-particle and point -particle) is computed as a Lennard-Jones interaction, using the -standard formula on the "pair_style lj/cut"_pair_lj.html doc page. -The espilon and sigma values are based on the atom type of the parent -body particle. +The interaction between two sub-particles, or a sub-particle and point +particle, or betwee two point particles is computed as a Lennard-Jones +interaction, using the standard formula + +:c,image(Eqs/pair_lj.jpg) + +where Rc is the cutoff. As explained above, an interaction involving +one or two body sub-particles may be computed even for r > Rc. For style {body}, the following coefficients must be defined for each pair of atoms types via the "pair_coeff"_pair_coeff.html command as in