This package provides methods for performing free energy perturbation simulations with soft-core pair potentials in LAMMPS. See the doc page for the fix adapt/fep command to get started. There are example scripts for using this package in examples/USER/fep. There are auxiliary tools for using this package in tools/fep. The person who created this package is Agilio Padua at Université Blaise Pascal Clermont-Ferrand (agilio.padua at univ-bpclermont.fr) Contact him directly if you have questions.