https://en.wikipedia.org/wiki/Wolfe_conditions https://en.wikipedia.org/wiki/Wolfe_conditions This is what you want for step length in a line search for most s

https://en.wikipedia.org/wiki/Wolfe_conditions https://en.wikipedia.org/wiki/Wolfe_conditions This is what you want for step length in a line search for most smooth continuous unconstrained optimizations. Really a lot more important than I had expected. The post is about LLS, which is a special case.