Plot fit

Usage: plot fit x y s f1...

List mode: The command performs a linear least-squares fit of the basis functions given bythe vector expressions f1,... to the data points with x-coordinates, y-coordinates and errors given by the vector expressions x, y and s, respectively. For m basis functions, f1,...,fm the optimal linear combination, is determined by minimizing the chi^2 value. The optimal fit function is added as another column to the list data. This command does not draw anything. The fit parameters, their standard deviations, and the probability that this value of chi^2 would be exceeded by chance are available through the intrinsic functions fitpar, fiterr, fitchisq and fitprob, respectively. If the errors of the data points are unkown, this can be indicated by setting s to zero in the fit command.