MEAMfit: A reference-free modified embedded atom method (RF-MEAM) energy and force-fitting code

Abstract

MEAMfit v1.02. Changes: various bug fixes; speed of single-shot energy and force calculations (not optimization) increased by ×10; elements up to Cn (Z=112) now correctly read from vasprun.xml files; EAM fits now produce Camelion output files; changed max number of vasprun.xml files to 10,000 (an unnecessary lower limit of 10 was allowed in the previous version). New version program summaryProgram title: MEAMfitCatalogue identifier: AEWY_v1_1Program summary URL:http://cpc.cs.qub.ac.uk/summaries/AEWY_v1_1.htmlProgram obtainable from: CPC Program Library, Queen’s University, Belfast, N. IrelandLicensing provisions: BSD 2-Clause LicenseNo. of lines in distributed program, including test data, etc.: 5202334No. of bytes in distributed program, including test data, etc.: 66637698Distribution format: tar.gzProgramming language: Fortran.Computer: Linux based workstations.Operating system: Linux.RAM: 120 MBClassification: 16.1.Catalogue identifier of previous version: AEWY_v1_0Journal reference of previous version: Comput. Phys. Comm. 196 (2015) 439External routines: TOMS611 Unconstrained Minimization [1] included in the MEAMfit code.Does the new version supersede the previous version?: YesNature of problem: Fitting embedded atom method (EAM) and reference-free modified embedded atom method (RF-MEAM) potentials [2–3] to energies and forces produced by VASP [4–7].Solution method: A computer program is presented which uses a conjugate-gradient minimizer paired with a genetic algorithm to fit EAM and RF-MEAM potentials to energies and/or atomic forces read directly from VASP output files. Potentials produced by the code are directly usable with the LAMMPS [8] or Camelion [9] molecular-dynamics packages.Reasons for new version: Bugs fixed; improvements made.Summary of revisions: Various bug fixes; speed of single-shot energy and force calculations (not optimization) increased by ×10; elements up to Cn (Z=112) now correctly read from vasprun.xml files; EAM fits now produce Camelion output files; changed max number of vasprun.xml files to 10,000 (an unnecessary lower limit of 10 was allowed in the previous version).Additional comments:User manual provided.!!!!! The distribution file for this program is over 65 MB and therefore is not delivered directly when download or Email is requested. Instead a html file giving details of how the program can be obtained is sent. !!!!!Running time: The run-time depends on the required level of accuracy of the final potential. For an EAM potential fit to 670 energies, a few hours on a single core is usually sufficient to produce a potential with R=12%–13% (see Equation. 9 in main-text for definition). To ensure a maximally optimized potential however (R=12%), a run-time of 24 h is recommended. To optimize a RF-MEAM potential, a further 24 h should be allowed. One will already find an improvement over the EAM using just a single core, however to ensure a maximally optimized potential, one should run several instances of MEAMfit in parallel.