# kim property example
#
# For detailed information of this example please refer to:
# `https://openkim.org/doc/evaluation/tutorial-lammps/`
#
# Description:
#
# This example is designed to calculate the cohesive energy corresponding to
# the equilibrium FCC lattice constant for
# `LJ_Shifted_Bernardes_1958MedCutoff_Ar__MO_126566794224_004` model for
# argon. The material properties computed in LAMMPS are represented as a
# standard KIM property instance format. (See
# `https://openkim.org/doc/schema/properties-framework/` and
# `https://docs.lammps.org/kim_commands.html` for further details).
# Then the created property instance is written to a file named `results.edn`
# using the `kim property dump` command.
#
# Requirement:
#
# This example requires LAMMPS built with the Python 3.6 or later package
# installed. See the `https://docs.lammps.org/python.html` doc page for
# more info on building LAMMPS with the version of Python on your system.
# After successfully building LAMMPS with Python, you need to install the
# kim-property Python package, See the
# `https://docs.lammps.org/Build_extras.html#kim` doc page for
# further details.
#
# This example requires that the KIM Portable Model (PM)
# `LJ_Shifted_Bernardes_1958MedCutoff_Ar__MO_126566794224_004`
# is installed.  This can be done with the command
#   kim-api-collections-management install user LJ_Shifted_Bernardes_1958MedCutoff_Ar__MO_126566794224_004
# If this command does not work, you may need to setup your PATH to find the utility.
# If you installed the kim-api using the LAMMPS CMake build, you can do the following
# (where the current working directory is assumed to be the LAMMPS build directory)
#   source ./kim_build-prefix/bin/kim-api-activate
# If you installed the kim-api using the LAMMPS Make build, you can do the following
# (where the current working directory is assumed to be the LAMMPS src directory)
#   source ../lib/kim/installed-kim-api-X.Y.Z/bin/kim-api-activate
# (where you should relplace X.Y.Z with the appropriate kim-api version number).
#
# Or, see `https://openkim.org/doc/obtaining-models` for alternative options.
#

# Initialize interatomic potential (KIM model) and units
atom_style atomic

# Set the OpenKIM model that will be used
kim init LJ_Shifted_Bernardes_1958MedCutoff_Ar__MO_126566794224_004 metal

# the equilibrium lattice constant for the fcc structure
variable lattice_constant equal 5.248509056866169

# Periodic boundary conditions along all three dimensions
boundary p p p

# Create an FCC lattice with the lattice spacing
# using a single conventional (orthogonal) unit cell
lattice      fcc ${lattice_constant}
region box   block 0 1 0 1 0 1 units lattice
create_box   1 box
create_atoms 1 box
mass         1 39.948

# Specify the KIM interactions
kim interactions Ar

# Compute energy
run 0

# Get cohesive energy
variable natoms       equal "count(all)"
variable ecohesive    equal "-pe/v_natoms"

# Create a property instance
kim property create 1 cohesive-potential-energy-cubic-crystal

# Set all the key-value pairs for this property instance
kim property modify 1 key short-name source-value 1 fcc                          &
                      key species source-value 1 Ar                              &
                      key a source-value ${lattice_constant}                     &
                            source-unit angstrom                                 &
                      key basis-atom-coordinates source-value 1 1:3 0.0 0.0 0.0  &
                                                 source-value 2 1:3 0.0 0.5 0.5  &
                                                 source-value 3 1:3 0.5 0.0 0.5  &
                                                 source-value 4 1:3 0.5 0.5 0.0  &
                      key space-group source-value Fm-3m                         &
                      key cohesive-potential-energy source-value ${ecohesive}    &
                                                    source-unit eV

# Dump the results in a file
kim property dump "results.edn"