Fitting session is started by fit_only() method. This method performs 1 fitting run. The best fit parameters after this run will be automatically used as initial parameters for the next fit_only() run.
IMPORTANT NOTE: It is absolutely pointless to proceed with determination of confidence intervals for model parameters if the model DOES NOT FIT! It may happen due to true mismatch between the model and the data or if the algorithm got trapped in a local minimum. To prevent the latter situation use grid_search_fit_only() method.
For a specific usage see TotalFit.m