From ac5bd8a4f7e7f759a0505afa3f3cbdf97fcbb846 Mon Sep 17 00:00:00 2001 From: Axel Kohlmeyer Date: Thu, 8 Apr 2021 08:44:18 -0400 Subject: [PATCH] correct the description of how the F dot r contributions are computed --- doc/src/compute_pressure.rst | 15 ++++++++------- 1 file changed, 8 insertions(+), 7 deletions(-) diff --git a/doc/src/compute_pressure.rst b/doc/src/compute_pressure.rst index f69f70daba..3c98208261 100644 --- a/doc/src/compute_pressure.rst +++ b/doc/src/compute_pressure.rst @@ -46,13 +46,14 @@ system volume (or area in 2d). The second term is the virial, equal to -dU/dV, computed for all pairwise as well as 2-body, 3-body, 4-body, many-body, and long-range interactions, where :math:`r_i` and :math:`f_i` are the position and force vector of atom *i*, and the black -dot indicates a dot product. When periodic boundary conditions are -used, N' necessarily includes periodic image (ghost) atoms outside the -central box, and the position and force vectors of ghost atoms are thus -included in the summation. When periodic boundary conditions are not -used, N' = N = the number of atoms in the system. :doc:`Fixes ` -that impose constraints (e.g. the :doc:`fix shake ` command) -also contribute to the virial term. +dot indicates a dot product. This is computed in parallel for each +sub-domain and then summed over all parallel processes. Thus N' +necessarily includes atoms from neighboring sub-domains (so-called ghost +atoms) and the position and force vectors of ghost atoms are thus +included in the summation. Only when running in serial and without +periodic boundary conditions is N' = N = the number of atoms in the +system. :doc:`Fixes ` that impose constraints (e.g. the :doc:`fix +shake ` command) may also contribute to the virial term. A symmetric pressure tensor, stored as a 6-element vector, is also calculated by this compute. The 6 components of the vector are