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Exact simulation of Poisson-Dirichlet distribution and generalised gamma process

Dassios, Angelos ORCID: 0000-0002-3968-2366 and Zhang, Junyi ORCID: 0000-0001-8986-6588 (2023) Exact simulation of Poisson-Dirichlet distribution and generalised gamma process. Methodology and Computing in Applied Probability, 25 (2). ISSN 1387-5841

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Identification Number: 10.1007/s11009-023-10040-3


Let J1> J2> ⋯ be the ranked jumps of a gamma process τα on the time interval [0 , α] , such that τα=∑k=1∞Jk . In this paper, we design an algorithm that samples from the random vector (J1,⋯,JN,∑k=N+1∞Jk) . Our algorithm provides an analog to the well-established inverse Lévy measure (ILM) algorithm by replacing the numerical inversion of exponential integral with an acceptance-rejection step. This research is motivated by the construction of Dirichlet process prior in Bayesian nonparametric statistics. The prior assigns weight to each atom according to a GEM distribution, and the simulation algorithm enables us to sample from the N largest random weights of the prior. Then we extend the simulation algorithm to a generalised gamma process. The simulation problem of inhomogeneous processes will also be considered. Numerical implementations are provided to illustrate the effectiveness of our algorithms.

Item Type: Article
Official URL:
Additional Information: © 2023 The Author(s).
Divisions: Statistics
Subjects: H Social Sciences > HA Statistics
Q Science > QA Mathematics
Date Deposited: 14 Jul 2023 14:18
Last Modified: 19 May 2024 04:09

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