minimize function within bounds

[wkotlarski]

@Expander, I've written an interface to the unitarity limit calculation by Mark and Florian. I'm missing only one piece. I've scattering matrix eigenvalues and I need to find their minimum (actually their maximum but I can flip the sign). It would be good to specify the range within which the minimum should be searched for. Our current minimizer only takes a single start argument. Would it be possible to add it? I'm basicaly trying to reproduce behaviour of flags 442 and 443 from Sec. 4.2.2 from here.

[Expander]

I think one would need to write a dedicated minimizer for such a use case or modify the algorithm of Minimizer, because the (naive) algorithm implemented in Minimizer just stops when it reaches a minimum, ignoring all bounds.

[wkotlarski]

The idea would be to use One Dimensional Minimization. One potential issue is that it defines a gsl_function type. This however collides with

static double gsl_function(const gsl_vector*, void*);

The difference compared to the multidimensional case is that what is called there gsl_multimin_function is called gsl_function here.