By setting the PATH MINIMIZATION keyword you can perform Mean Free Energy Path searches[128]. The details of the method are controlled by keywords in the &PATH section. However, the space of collective variables in which the search will be performed has to be defined using RESTRAINTS in the &ATOMS input file section (for details see 11.5.2 of the manual). The initial string in this collective variable space is read in an external file string.inp. This file contains one line per replica, each giving first the replica index and then the list of collective variables values. The basename for directories where each replica is run should also be specified using the FILEPATH, or else the environment variable CPMD_FILEPATH.