Consider using first derivative information for step size calculation in minimization about kappa

[ajkerr0]

Refer to Numerical Recipes again or find another numerical methods resource.

[ajkerr0]

I think they are used primarily to determine the relative location from the minimum. For example if del E dot p < 0, where p is the search direction, then p is a descent direction. This can determine if we're past the minimum or haven't yet reached it.

[ajkerr0]

Again,this issue is a remnant of when minimization wasn't working correctly all the time. First derivative information may be used for specific line search methods, otherwise this issue should be ignored. Closing.