Running machine-learned force fields in LAMMPS - Revision history

Singraber at 10:43, 30 March 2026

2026-03-30T10:43:10Z

← Older revision		Revision as of 10:43, 30 March 2026
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	== Using traditional make (only for VASP 6.5.X) ==		== Using traditional make (only for VASP 6.5.X) ==

	Before starting the LAMMPS build please either compile {{VASP}} with the ~~[[VASPml library#Build instructions\|~~VASPml library]], or alternatively, keep your {{VASP}} installation untouched and perform a [[VASPml library#Standalone build instructions\|standalone build]] of the VASPml library. To confirm that everything is ready we can check for the presence of the following files:		Before starting the LAMMPS build please either compile [[Makefile.include#VASPml_(experimental)\|{{VASP}} with the VASPml library]], or alternatively, keep your {{VASP}} installation untouched and perform a [[VASPml library#Standalone build instructions\|standalone build]] of the VASPml library. To confirm that everything is ready we can check for the presence of the following files:

	* For a {{VASP}} build with VASPml:		* For a {{VASP}} build with VASPml:

Singraber: /* Using CMake ({{VASP}} 6.6.0 and later) */

2026-03-30T10:42:22Z

Using CMake ({{VASP}} 6.6.0 and later)

← Older revision		Revision as of 10:42, 30 March 2026
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	== Using CMake ({{VASP}} 6.6.0 and later) ==		== Using CMake ({{VASP}} 6.6.0 and later) ==

	{{NB\|~~warning\|Under construction~~, to ~~be updated soon~~...}}		Before starting the LAMMPS build please either compile [[Makefile.include#VASPml_(experimental)\|{{VASP}} with the VASPml library]], or alternatively, keep your {{VASP}} installation untouched and perform a [[VASPml library#Standalone build instructions\|standalone build]] of the VASPml library. Optionally, if you want to confirm that everything is ready you can check for the presence of the following files:
	~~<syntaxhighlight lang="python">~~
	git clone https://github.com/vasp-dev/lammps~~.git~~		* <code>/path/to/vaspml/lib/libvaspml.a</code>,
	cd lammps		* <code>/path/to/vaspml/build/libvaspml/InterfaceLAMMPS.hpp</code>,
	git checkout vasp-mlff-6.6.0
	cmake -S cmake -B build -DPKG_ML-VASP=yes -DVASPML_DIR=/path/to/vaspml		where, in case of a build together with {{VASP}}, VASPml is located inside of <code>/path/to/vasp/build/VERSION</code>, where <code>VERSION</code> is any of <code>std</code>, <code>gam</code> or <code>ncl</code>. It does not matter which {{VASP}} build version is used because the VASPml library will be identical in all three cases.
	cmake --build build
	</~~syntaxhighlight~~>		Next, we need to obtain the LAMMPS source code with the patch for VASPml. Please clone the following repository to your hard disk and change into the LAMMPS root directory:

			git clone https://github.com/vasp-dev/lammps
			cd lammps

			At this point looking around in the git repository will show the files from the <code>develop</code> branch (the main development branch of LAMMPS). However, the patch files are located in another branch, hence we need to switch with this command:

			git checkout vasp-mlff-6.6.0

			Now we configure the [https://docs.lammps.org/Build_cmake.html LAMMPS build with CMake] where <code>PKG_ML-VASP</code> and <code>VASPML_DIR</code> need to be set:

			cmake -S cmake -B build -DPKG_ML-VASP=yes -DVASPML_DIR=/path/to/vaspml

			With this command CMake checks the available compilers and libraries and reports if anything is missing. Please check if the output is consistent with the toolchain selected for building {{VASP}} or standalone VASPml. In case CMake does not correctly determine the compiler and libraries it may be necessary to pass them explicitly with [https://cmake.org/cmake/help/latest/manual/cmake-variables.7.html standard CMake variables], like <code>-DCMAKE_CXX_COMPILER=...</code> and <code>-DCMAKE_CXX_FLAGS=...</code> for specifying the C++ compiler and command line arguments, respectively. Finally, in the output you should see these lines confirming that VASPml has been found:

			-- Found VASPml: /path/to/vaspml
			-- Found VASPml library: /path/to/vaspml/lib/libvaspml.a
			-- Found VASPml include directory: /path/to/vaspml/build/libvaspml

			If the previous CMake command exited successfully, LAMMPS can be built with

			cmake --build build

			Adding the <code>-j</code> flag allows the build process to run in parallel. The LAMMPS executable <code>lmp</code> will be located inside the <code>build</code> directory.

	= Setting up a LAMMPS MD run =		= Setting up a LAMMPS MD run =

Singraber: /* Using CMake ({{VASP}} 6.6.0 and later) */

2026-03-27T23:03:58Z

Using CMake ({{VASP}} 6.6.0 and later)

← Older revision		Revision as of 23:03, 27 March 2026
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	{{NB\|warning\|Under construction, to be updated soon...}}		{{NB\|warning\|Under construction, to be updated soon...}}
			<syntaxhighlight lang="python">
			git clone https://github.com/vasp-dev/lammps.git
			cd lammps
			git checkout vasp-mlff-6.6.0
			cmake -S cmake -B build -DPKG_ML-VASP=yes -DVASPML_DIR=/path/to/vaspml
			cmake --build build
			</syntaxhighlight>

	= Setting up a LAMMPS MD run =		= Setting up a LAMMPS MD run =

Singraber at 14:07, 27 March 2026

2026-03-27T14:07:22Z

← Older revision		Revision as of 14:07, 27 March 2026
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	= Building LAMMPS with VASPml patch =		= Building LAMMPS with VASPml patch =

			The LAMMPS packages offers two distinct build pathways: via [https://cmake.org/ CMake] or via traditional makefiles. While the latter was available at the time of the first VASPml release in {{VASP}} 6.5.0, it since has been slowly phased out. Hence, starting with {{VASP}} 6.6.0 building LAMMPS with VASPml patch is only supported via CMake.

			== Using traditional make (only for VASP 6.5.X) ==

	Before starting the LAMMPS build please either compile {{VASP}} with the [[VASPml library#Build instructions\|VASPml library]], or alternatively, keep your {{VASP}} installation untouched and perform a [[VASPml library#Standalone build instructions\|standalone build]] of the VASPml library. To confirm that everything is ready we can check for the presence of the following files:		Before starting the LAMMPS build please either compile {{VASP}} with the [[VASPml library#Build instructions\|VASPml library]], or alternatively, keep your {{VASP}} installation untouched and perform a [[VASPml library#Standalone build instructions\|standalone build]] of the VASPml library. To confirm that everything is ready we can check for the presence of the following files:
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	Optionally, add the <code>-j</code> flag to perform a parallel build (faster). If the build process succeeds the LAMMPS executable <code>lmp_mpi</code> will be located in the <code>lammps/src</code> directory.		Optionally, add the <code>-j</code> flag to perform a parallel build (faster). If the build process succeeds the LAMMPS executable <code>lmp_mpi</code> will be located in the <code>lammps/src</code> directory.

			== Using CMake ({{VASP}} 6.6.0 and later) ==

			{{NB\|warning\|Under construction, to be updated soon...}}

	= Setting up a LAMMPS MD run =		= Setting up a LAMMPS MD run =

Singraber at 07:50, 20 February 2025

2025-02-20T07:50:34Z

← Older revision		Revision as of 07:50, 20 February 2025
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	[https://www.lammps.org LAMMPS] is a very popular molecular dynamics (MD) package which implements lots of advanced simulation methods. Although {{VASP}} itself also offers [[:Category:Molecular_dynamics\|MD simulations]] LAMMPS provides more flexibility and additional methods (e.g. thermostats/barostats, grouping atoms, etc.). This page describes how to make pre-trained {{VASP}} machine-learned force fields available within LAMMPS. On a technical level this is achieved by patching the LAMMPS source code in such way that a new [https://docs.lammps.org/pair_style.html <code>pair_style</code>] named <code>vasp</code> is available in the LAMMPS script language. The patched LAMMPS source is compiled and then linked to the [[VASPml library]]. The first section describes in detail how to patch and compile LAMMPS. The second section explains how the {{VASP}} {{FILE\|ML_FF}} file can be loaded in a LAMMPS script.		[https://www.lammps.org LAMMPS] is a very popular molecular dynamics (MD) package which implements lots of advanced simulation methods. Although {{VASP}} itself also offers [[:Category:Molecular_dynamics\|MD simulations]] LAMMPS provides more flexibility and additional methods (e.g. thermostats/barostats, grouping atoms, etc.). This page describes how to make pre-trained {{VASP}} machine-learned force fields available within LAMMPS. On a technical level this is achieved by patching the LAMMPS source code in such way that a new [https://docs.lammps.org/pair_style.html <code>pair_style</code>] named <code>vasp</code> is available in the LAMMPS script language. The patched LAMMPS source is compiled and then linked to the [[VASPml library]]. The first section describes in detail how to patch and compile LAMMPS. The second section explains how the {{VASP}} {{FILE\|ML_FF}} file can be loaded in a LAMMPS script.
	{{NB\|warning\|The VASPml library and therefore also the LAMMPS interface are experimental features. Please carefully check results and, if feasible, compare against similar VASP MD simulations.}}		{{NB\|warning\|The VASPml library available as of {{VASP}} 6.5.0 and therefore also the LAMMPS interface are experimental features. Please carefully check results and, if feasible, compare against similar VASP MD simulations.}}

	= Building LAMMPS with VASPml patch =		= Building LAMMPS with VASPml patch =

Singraber: /* Building LAMMPS with VASPml patch */

2025-02-19T09:46:01Z

Building LAMMPS with VASPml patch

← Older revision		Revision as of 09:46, 19 February 2025
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	= Building LAMMPS with VASPml patch =		= Building LAMMPS with VASPml patch =

	Before starting the LAMMPS build please compile {{VASP}} with the [[VASPml library#Build instructions\|VASPml library]]~~. Alternatively~~, keep your {{VASP}} installation untouched and perform a [[VASPml library#Standalone build instructions\|standalone build]] of the VASPml library. To confirm that everything is ready we can check for the presence of the following files:		Before starting the LAMMPS build please either compile {{VASP}} with the [[VASPml library#Build instructions\|VASPml library]], or alternatively, keep your {{VASP}} installation untouched and perform a [[VASPml library#Standalone build instructions\|standalone build]] of the VASPml library. To confirm that everything is ready we can check for the presence of the following files:

	* For a {{VASP}} build with VASPml:		* For a {{VASP}} build with VASPml:

Singraber at 09:29, 19 February 2025

2025-02-19T09:29:48Z

← Older revision		Revision as of 09:29, 19 February 2025
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	= Building LAMMPS with VASPml patch =		= Building LAMMPS with VASPml patch =

	Before starting the LAMMPS build please compile {{VASP}} with the [[VASPml library#Build instructions\|VASPml library]]. To confirm that everything is ready we can check for the presence of the following files:		Before starting the LAMMPS build please compile {{VASP}} with the [[VASPml library#Build instructions\|VASPml library]]. Alternatively, keep your {{VASP}} installation untouched and perform a [[VASPml library#Standalone build instructions\|standalone build]] of the VASPml library. To confirm that everything is ready we can check for the presence of the following files:

	* <code>/path/to/vasp/build/VERSION/vaspml/lib/libvaspml.a</code>		* For a {{VASP}} build with VASPml:
	* <code>/path/to/vasp/build/VERSION/vaspml/include/InterfaceLAMMPS.hpp</code>		** <code>/path/to/vasp/build/VERSION/vaspml/lib/libvaspml.a</code>
			** <code>/path/to/vasp/build/VERSION/vaspml/include/InterfaceLAMMPS.hpp</code>

	where <code>VERSION</code> is any of <code>std</code>, <code>gam</code> or <code>ncl</code>. It does not matter which {{VASP}} build version is used because the VASPml library will be identical in all three cases.		where <code>VERSION</code> is any of <code>std</code>, <code>gam</code> or <code>ncl</code>. It does not matter which {{VASP}} build version is used because the VASPml library will be identical in all three cases.

			* Or, alternatively, for a [[VASPml library#Standalone build instructions\|VASPml standalone build]] please check:
			** <code>/path/to/vaspml/lib/libvaspml.a</code>
			** <code>/path/to/vaspml/include/InterfaceLAMMPS.hpp</code>

	Next, we need to obtain the LAMMPS source code with the patch for VASPml. Please clone the following repository to your hard disk and change into the LAMMPS root directory:		Next, we need to obtain the LAMMPS source code with the patch for VASPml. Please clone the following repository to your hard disk and change into the LAMMPS root directory:
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	git checkout vasp-mlff		git checkout vasp-mlff

	Then, while still in the LAMMPS root directory we need to create a symbolic link from <code>lammps/lib/vasp/vaspml</code> to the actual location of the VASPml folder:		Then, while still in the LAMMPS root directory we need to create a symbolic link from <code>lammps/lib/vasp/vaspml</code> to the actual location of the VASPml folder.

			* In case of a {{VASP}} build with VASPml: {{CB\|ln -s /path/to/vasp/build/std/vaspml lib/vasp/\|:}} Again, it is not important which of the three {{VASP}} build directories (<code>std</code>, <code>gam</code> or <code>ncl</code>) is used because the VASPml library is the same.

	ln -s /path/to~~/vasp/build/std~~/vaspml lib/vasp/		* Alternatively, for a standalone VASPml build: {{CB\|ln -s /path/to/vaspml lib/vasp/\|:}}

	~~Again, it is not important which of the three {{VASP}} build directories (<code>std</code>, <code>gam</code> or <code>ncl</code>) is used because the VASPml library is the same.~~ For the remaining steps we need to change into the <code>src</code> directory:		For the remaining steps we need to change into the <code>src</code> directory:

	cd src		cd src

Singraber at 14:35, 11 February 2025

2025-02-11T14:35:58Z

← Older revision		Revision as of 14:35, 11 February 2025
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	= Setting up a LAMMPS MD run =		= Setting up a LAMMPS MD run =

			{{NB\|warning\|Please always review the current [[VASPml library#Restrictions\|limitations and bug reports]].}}

	LAMMPS comes with its own powerful script language which allows the user to specify all relevant MD simulation parameters in a single file. Please consult the [https://docs.lammps.org/Commands_input.html LAMMPS documentation] for details. Within the LAMMPS script language the commands <code>pair_style</code> and <code>pair_coeff</code> are responsible for selecting a force field. The <code>ML-VASP</code> package introduces a new <code>pair_style</code> called <code>vasp</code>. The <code>pair_style vasp</code> command does not have any additional arguments, all configurable settings are given as arguments to the <code>pair_coeff</code> command in this format:		LAMMPS comes with its own powerful script language which allows the user to specify all relevant MD simulation parameters in a single file. Please consult the [https://docs.lammps.org/Commands_input.html LAMMPS documentation] for details. Within the LAMMPS script language the commands <code>pair_style</code> and <code>pair_coeff</code> are responsible for selecting a force field. The <code>ML-VASP</code> package introduces a new <code>pair_style</code> called <code>vasp</code>. The <code>pair_style vasp</code> command does not have any additional arguments, all configurable settings are given as arguments to the <code>pair_coeff</code> command in this format:

Huebsch: /* Setting up a LAMMPS MD run */

2025-02-05T11:07:11Z

Setting up a LAMMPS MD run

← Older revision		Revision as of 11:07, 5 February 2025
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	<pre>pair_style vasp		<pre>pair_style vasp
	pair_coeff * * file types</pre>		pair_coeff * * file types</pre>
	The <code>pair_coeff</code> command must be followed by <code>* *</code>, then followed by the name of the {{VASP}} force field file, typically <code>ML_FF</code>. Finally, there comes a mapping from LAMMPS atom types to {{VASP}} force field types, e.g., <code>H O Na Cl</code> means that LAMMPS types <code>1</code>, <code>2</code>, <code>3</code> and <code>4</code> are mapped to {{VASP}} types <code>H</code>, <code>O</code>, <code>Na</code> and <code>Cl</code>, respectively. A valid example may look like this:		The <code>pair_coeff</code> command must be followed by <code>* *</code>, then followed by the name of the {{VASP}} force field file, typically <code>ML_FF</code>. Finally, there comes a mapping from LAMMPS atom types to {{VASP}} force-field types, e.g., <code>H O Na Cl</code> means that LAMMPS types <code>1</code>, <code>2</code>, <code>3</code> and <code>4</code> are mapped to {{VASP}} types <code>H</code>, <code>O</code>, <code>Na</code> and <code>Cl</code>, respectively. A valid example may look like this:

	<pre>pair_style vasp		<pre>pair_style vasp

Singraber at 08:36, 24 January 2025

2025-01-24T08:36:48Z

← Older revision		Revision as of 08:36, 24 January 2025
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	The <code>pair_style vasp</code> expects input coordinates to be in the units of Ångström and returns energies and forces with the energy unit of eV. Hence, it is only compatible with the LAMMPS setting <code>units metal</code> in the input script, otherwise an error will occur.		The <code>pair_style vasp</code> expects input coordinates to be in the units of Ångström and returns energies and forces with the energy unit of eV. Hence, it is only compatible with the LAMMPS setting <code>units metal</code> in the input script, otherwise an error will occur.

	~~<!---~~[[Category:Machine-learned force fields]]		[[Category:Machine-learned force fields]]
	[[Category:Howto]]~~--->~~		[[Category:Howto]]