  Inspired by thermodynamic integration, we propose a method for the
calculation of time-independent free energy profiles from history-dependent
biased simulations via Mean Force Integration (MFI). MFI circumvents the need
for computing the ensemble average of the bias acting on the system c(t) and
can be applied to different variants of metadynamics. Moreover, MFI naturally
extends to aggregate information obtained from independent metadynamics
simulations, allowing to converge free energy surfaces without the need to
sample recrossing events in a single continuous trajectory. We validate MFI
against one- and two-dimensional analytical potentials and by computing the
conformational free energy landscape of ibuprofen in the bulk of its most
common crystal phase.
