add_library(
    ions
    OBJECT
    Cell_PW.cpp
    bfgs_basic.cpp
    ions.cpp
    ions_move_basic.cpp
    ions_move_bfgs.cpp
    ions_move_cg.cpp
    ions_move_methods.cpp
    ions_move_sd.cpp
    lattice_change_basic.cpp
    lattice_change_cg.cpp
    lattice_change_methods.cpp
    variable_cell.cpp
)
