From 0a5fa89f9cebd0fd315a300142788302d945483c Mon Sep 17 00:00:00 2001 From: Yifan Li Date: Sun, 17 Sep 2023 10:50:26 -0500 Subject: [PATCH] add LAMMPS units discussion in document --- doc/third-party/lammps-command.md | 10 ++++++++++ 1 file changed, 10 insertions(+) diff --git a/doc/third-party/lammps-command.md b/doc/third-party/lammps-command.md index e1d482381f..f4990c30bb 100644 --- a/doc/third-party/lammps-command.md +++ b/doc/third-party/lammps-command.md @@ -1,5 +1,14 @@ # LAMMPS commands +## units +All units in LAMMPS except `lj` are supported. `lj` is not supported. + +The most commonly used units are `metal`, since the internal units of distance, energy, force, and charge in DeePMD-kit are `\AA`, `eV`, `eV / \AA`, and `proton charge`, respectively. These units are consistent with the `metal` units in LAMMPS. + +If one wants to use other units like `real` or `si`, it is welcome to do so. There is no need to do the unit conversion mannualy. The unit conversion is done automatically by LAMMPS. + +The only thing that one needs to take care is the unit of the output of `compute deeptensor/atom`. Working with `metal` units for `compute deeptensor/atom` is totally fine, since there is no unit conversion. For other unit styles, we currently assume that the output of the `compute deeptensor/atom` command has the unit of distance and have applied the unit conversion factor of distance. If a user wants to infer quantities with units other than distance, the user is encouraged to open a GitHub feature request, so that the unit conversion factor can be added. + ## Enable DeePMD-kit plugin (plugin mode) If you are using the plugin mode, enable DeePMD-kit package in LAMMPS with `plugin` command: @@ -119,6 +128,7 @@ dump 1 all custom 100 water.dump id type c_dipole[1] c_dipole[2] c_di ### Restrictions - The `deeptensor/atom` compute is provided in the USER-DEEPMD package, which is compiled from the DeePMD-kit, visit the [DeePMD-kit website](https://github.com/deepmodeling/deepmd-kit) for more information. +- For the issue of using a unit style for `compute deeptensor/atom`, refer to the discussions in [units](#units) of this page. ## Long-range interaction