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无似然时基于校准核与比率估计的后验推断方法

熊逸飞, 张三国   

  1. 中国科学院大学数学科学学院, 北京 100049; 中国科学院大数据挖掘与知识管理重点实验室, 北京 100049
  • 收稿日期:2024-01-26 修回日期:2024-04-15 发布日期:2024-05-22

Calibration kernel-based ratio estimation for likelihood-free posterior inference

XIONG Yifei, ZHANG Sanguo   

  1. School of Mathematical Sciences, University of Chinese Academy of Sciences, Beijing 100049, China; Key Laboratory of Big Data Mining and Knowledge Management, University of Chinese Academy of Sciences, Beijing 100049, China
  • Received:2024-01-26 Revised:2024-04-15 Published:2024-05-22
  • Contact: E-mail: sgzhang@ucas.ac.cn
  • Supported by:
    *Supported by the National Natural Science Foundation of China No.12171454, U19B2940 and Fundamental Research Funds for the Central Universities

摘要: 在贝叶斯推断中常遇到的一个困难是似然函数难以评估或没有显示的表达式,这种情况被称为无似然贝叶斯问题,此时后验分布只能通过基于特定参数生成的样本来间接推断。无似然贝叶斯问题的主要挑战之一是如何在有限的样本生成次数内有效逼近后验分布,现有的计算方法包括近似贝叶斯计算、合成似然及贝叶斯优化等。Miller等(2022)提出了一种新的序贯比率估计方法,创新地将似然与证据比的估计转化为多分类问题,从而高效地推断后验分布。基于此方法,本研究进一步发展了一种基于校准核的比率估计新方法:校准比率后验推断方法,通过校准核为分类任务的样本赋予额外权重,增强了原方法的训练效率和性能。本文首先说明了新方法的收敛性,随后通过数值实验验证了其在有限样本生成条件下在多个指标上对参数后验分布估计的准确度有显著提高。

关键词: 无似然贝叶斯推断, 序贯比率估计, 对比学习

Abstract: Bayesian inference often faces challenges where the likelihood function is difficult to evaluate or lacks explicit expression, known as likelihood-free Bayesian problems, where posterior distributions can only be inferred indirectly through samples generated under specific parameters. Existing methods like approximate Bayesian computation, synthetic likelihood, and Bayesian optimization focus on address these issues. This paper extends Miller et al.'s (2022) sequential neural ratio estimation method for likelihood-free Bayesian problems by transforming likelihood-to-evidence ratio estimation into a multi-class problem for efficient posterior estimation. We introduce a new calibration kernel-based ratio estimation method (CKRE), to enhance the original method's training efficiency and performance. The convergence of our proposed methods is proven, and numerical experiments demonstrate its significant improvement in accurately estimating posterior distributions under limited sample generation conditions.

Key words: Likelihood-free Bayesian inference, Sequential neural ratio estimation, Contrastive learning

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