Greetings, If this is not the appropriate place to post this question please let me know where to post it. I have a package under development which fits models of the form $$ f(t)=\sum_i B_iG_i(t,\omega) $$ depending on a parameter vector $\omega$ of arbitrary dimension to data (one dimensional time series) in the general framework of the data = deterministic signal + Gaussian noise in the spirit of Bretthorst, G. Larry, 1988, "Bayesian Spectrum Analysis and Parameter Estimation," Lecture Notes in Statistics, vol. 48, Springer-Verlag, New York. The basic parametric model $$ G_i(t,\omega)=cos(\omega_i t), sin(\omega_i t) $$ corresponds to classical spectral analysis, however the model can (at least in principle) be completely general. The problem is that the models cannot be defined by the user but have to be hard coded (in C++ since the computations are substantial). I plan to include the ability to modify each model by the action of further parameters as: time changes: t -> t+omega, t -> omega*t, t -> t^omega model function change: G(t) -> sign(G(t))*|G(t)|^omega I plan to include models that can be generated by these actions from trig functions, some piecewise linear functions, monomials, and exponential function. My question is: what further parametric models are of sufficiently general interest to be included? Many thanks, Michael Meyer [[alternative HTML version deleted]]