Vectorize theoretical.cdf_from_ppf with scipy.optimize.elementwise.bracket_root on scipy>=1.15

[jorenham]

It's guaranteeed to find a bracket if the function is monotonic, which is (or should be) the case for quantile functions (i.e. the ppf argument of cdf_from_ppf).

According to the (upcoming) release notes:

Compared to existing functions (e.g.scipy.optimize.root_scalar and scipy.optimize.minimize_scalar), these functions can offer speedups of over 100x when used with NumPy arrays, and even greater gains are possible with other Array API Standard compatible array libraries (e.g. CuPy).

docs

SciPy 1.15.0 "final" is expected to be released on 2025-01-06.