Closed
Description
Description
Add incomplete beta inverse. This is needed for the quantile function of the beta distribution (if or when quantile functions get added). By having this available to users they can define the quantile function of the beta distribution as well as the quantile function of the skewed generalized t distribution
The function is available in boost at https://www.boost.org/doc/libs/1_74_0/libs/math/doc/html/math_toolkit/sf_beta/ibeta_inv_function.html
The derivative is defined at https://functions.wolfram.com/GammaBetaErf/InverseBetaRegularized/20/01/01/