Support added to LAMMPS to query for available KIM models

02-Mar-2021

One of the unique features of OpenKIM is that all models uploaded are automatically run against a suite of simulation codes and integrity checks via our processing pipeline (described in the Journal of Chemical Physics), and the results inserted into a public-facing database hosted at https://query.openkim.org.  Until now, the kim query command in LAMMPS could be used directly in input scripts to retrieve the predictions of the KIM model currently being used for various material properties.  We have recently extended the capabilities of this command so that it can be used to retrieve all available KIM models that support a given set of atomic species.  Below is an example of a LAMMPS input script illustrating how one can loop over all Embedded Atom Method (EAM) models in KIM that support aluminum and retrieve their fcc lattice constant:

# Get all EAM models in KIM that support Al (and possibly other elements) and
# store them in an index variable named 'model'.  To retrieve all EAM models
# that support *only* Al, the 'species_logic' option can be used
kim query model index get_available_models species=[Al] potential_type=[eam]
label model_loop
    kim query latconst get_lattice_constant_cubic crystal=[fcc] species=[Al]
units=[angstrom] model=[${model}]
    print "Using fcc lattice constant (${model}) of ${latconst} Angstroms"
    ...
    ...  [do something with current value of latconst]
    ...
next  model
jump  SELF model_loop

Notes:

  • The kim_* commands have been replaced by a single kim command that has subcommands.  Thus, for example, kim_query has become kim query.
  • In order to actually use a KIM model identified by a query, it must be installed locally on your system
  • See the Querying KIM Content docs page for more information on the different query commands available and their options
  • All of the changes above have been merged into the master branch of LAMMPS on GitHub and will be part of the next release