For linear Kramer's Kronig test, an equivalent circuit model is required to fit the measured impedance spectra. The governing equations for Kramer's Kronig test includes resistance and capacitance values of the said equivalent circuit. So, how can I choose the values of R and C to write a programming code for linear Kramer's Kronig test for my electrochemical impedance spectroscopy data sheet? Does cost function (J) has anything to do with it?