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arXiv 2006.09347cs.LGstat.ML
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Understanding and Mitigating Exploding Inverses in Invertible Neural Networks

University of Bremen(不来梅大学);University of Toronto(多伦多大学);Vector Institute(向量研究所)

Jens Behrmann, Paul Vicol, Kuan-Chieh Wang, Roger Grosse, Jörn-Henrik Jacobsen

英文摘要:

Invertible neural networks (INNs) have been used to design generative models, implement memory-saving gradient computation, and solve inverse problems. In this work, we show that commonly-used INN architectures suffer from exploding inverses and are thus prone to becoming numerically non-invertible. Across a wide range of INN use-cases, we reveal failures including the non-applicability of the change-of-variables formula on in- and out-of-distribution (OOD) data, incorrect gradients for memory-saving backprop, and the inability to sample from normalizing flow models. We further derive bi-Lipschitz properties of atomic building blocks of common architectures. These insights into the stability of INNs then provide ways forward to remedy these failures. For tasks where local invertibility is sufficient, like memory-saving backprop, we propose a flexible and efficient regularizer. For problems where global invertibility is necessary, such as applying normalizing flows on OOD data, we show the importance of designing stable INN building blocks.

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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