beta_inc function

The incomplete beta function and its inverse

Computes the incomplete beta function [REMOVE_ME]$I_x(a,b):=\int_0^x u^{a-1}(1-u)^{b-1}\,d\mathrm{u},\quad a,b>0I_x(a,b):=\int_0^x u^{a-1}(1-u)^{b-1}du, a,b>0 [REMOVE_ME_2]$

and its inverse function.

beta_inc(x, a, b, lower_tail = TRUE, log = FALSE)

beta_inc_inv(u, a, b, lower_tail = TRUE, log = FALSE)

Arguments

• x: a vector of size nx or a matrix of size c(nx, 1).
• a, b: scalars giving the parameters of the beta function.
• lower_tail: accumulate the probability from the lower tail? If FALSE, the probability is accumulated from the upper tail. Defaults to FALSE.
• log: use log-scale? If TRUE, returns the logarithm of the incomplete beta function and uses log-scale for u in beta_inc. Defaults to FALSE.
• u: a vector of probabilities of size nu or a matrix of size c(nu, 1).

Returns

• beta_inc: a matrix of size c(nx, 1) with the evaluation of the incomplete beta function at x.
• beta_inc_inv: a matrix of size c(nu, 1) with the evaluation of the inverse incomplete beta function at u.

Description

Computes the incomplete beta function

and its inverse function.

Details

The functions are mere wrappers to R's internal pbeta and qbeta functions.