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非参数变分推理

Nonparametric Variational Inference
课程网址: http://videolectures.net/nipsworkshops2012_hoffman_variational/  
主讲教师: Matt Hoffman
开课单位: Adobe公司
开课时间: 2013-01-16
课程语种: 英语
中文简介:
变分方法被广泛用于近似后验推断。然而,它们的使用通常限于具有特定共轭特性的分布族。为了避免这种限制,我们提出了一系列受非参数核密度估计启发的变分近似。这些内核的位置及其带宽被视为变分参数并进行优化,以提高数据边际可能性的近似下限。与大多数其他变分近似不同,使用多个核允许近似捕获后验的多个模式。我们用分层逻辑回归模型和非线性矩阵分解模型证明了非参数逼近的有效性。我们获得的预测性能与更专业的变分方法和MCMC近似一样好或更好。该方法易于应用于难以得出标准变分方法的图形模型。
课程简介: Variational methods are widely used for approximate posterior inference. However, their use is typically limited to families of distributions that enjoy particular conjugacy properties. To circumvent this limitation, we propose a family of variational approximations inspired by nonparametric kernel density estimation. The locations of these kernels and their bandwidth are treated as variational parameters and optimized to improve an approximate lower bound on the marginal likelihood of the data. Unlike most other variational approximations, using multiple kernels allows the approximation to capture multiple modes of the posterior. We demonstrate the e.cacy of the nonparametric approximation with a hierarchical logistic regression model and a nonlinear matrix factorization model. We obtain predictive performance as good as or better than more specialized variational methods and MCMC approximations. The method is easy to apply to graphical models for which standard variational methods are difficult to derive.
关 键 词: variational; nonparametric kernel density estimation; method
课程来源: 视频讲座网
最后编审: 2020-06-29:cxin
阅读次数: 331