In MFI, for each estimate of the mean force dF (s) ds , as well as accounting for the time dependent bias force dV (s,t) ds , the derivative of the biased probability density p b (s) between every two bias depositions in the time interval [t; t + τ ] is approximated using Gaussian kernel density functions. In the aforementioned time interval τ refers to the lag time between every two subsequent bias depositions. A bandwidth of h = 0.03 was used for the Gaussian kernels and the number of frames used to reconstruct the perturbed mean force term dp b (s)