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arXiv 0910.3301cs.AIcs.DS
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最大乘积消息传递的快速算法

Faster Algorithms for Max-Product Message-Passing

NICTA(澳大利亚国家信息与通信技术研究院);Australian National University(澳大利亚国立大学)

Julian J. McAuley, Tiberio S. Caetano

摘要:

图模型中的最大后验推理通常通过消息传递算法来解决,例如连接树算法或循环置信传播算法。众所周知,这个问题的精确解在模型被三角化后的最大团的大小上是指数的,而近似推理在模型的因子的大小上通常是指数的。在本文中,我们利用了这样一个事实,即许多模型的最大团大于其组成因子,并且许多因子完全由潜变量组成(即,它们不依赖于观察)。这在各种各样的应用程序中是常见的情况,包括网格、树和环形结构模型。在这种情况下,我们能够将消息传递的复杂性指数降低0.5,无论是精确推理还是近似推理。

英文摘要:

Maximum A Posteriori inference in graphical models is often solved via message-passing algorithms, such as the junction-tree algorithm, or loopy belief-propagation. The exact solution to this problem is well known to be exponential in the size of the model's maximal cliques after it is triangulated, while approximate inference is typically exponential in the size of the model's factors. In this paper, we take advantage of the fact that many models have maximal cliques that are larger than their constituent factors, and also of the fact that many factors consist entirely of latent variables (i.e., they do not depend on an observation). This is a common case in a wide variety of applications, including grids, trees, and ring-structured models. In such cases, we are able to decrease the exponent of complexity for message-passing by 0.5 for both exact and approximate inference.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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