The check for fitness being smaller than the last value should use the
absolute value, to mean the fitness isn't changing since last iteration.
It's currently always quiting the function after the first iteration.
However for Gauss Newton we anyway want to run as many iterations as we
can, because there are ups and downs along the iteration so we might get
say best result where before and after iterations were bad. The lines
above takes care that sane and the best is selected.
Siddharth Bharat Purohit
451c2f146d