Generate from extremal Dirichlet \(Y \sim {P_x}\), where \(P_{x}\) is the probability of extremal functions from a Dirichlet mixture
.rPdirmix(d, index, alpha, weight)
a d
-vector from \(P_x\)
dimension of the 1-sample
index of the location. An integer in 0, ..., \(d-1\)
a \(d \times n\) dimensional vector of positive parameter values for the Dirichlet vector
a m
vector of mixture weights, which sum to 1