reporting R-square for customised nonlinear model fit
I am trying to find the best way to report a nonlinear model fit to my experimental data. I have managed to write a script that fits a nonlinear model and finds the parameters estimates using the loss function. It then reports each parameter estimates and the non linear errors. However, I would like to get the RMSE or R-square of the resulting fit also. Is this not available for nonlinear model...