U-Statistics for Importance-Weighted Variational Inference
U-Statistics for Importance-Weighted Variational Inference
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DOI:
10.48550/arxiv.2302.13918
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发表时间:
2023-02
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影响因子:
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通讯作者:
Javier Burroni
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文献类型:
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作者:
Javier Burroni
We propose the use of U-statistics to reduce variance for gradient estimation in importance-weighted variational inference. The key observation is that, given a base gradient estimator that requires $m>1$ samples and a total of $n>m$ samples to be used for estimation, lower variance is achieved by averaging the base estimator on overlapping batches of size $m$ than disjoint batches, as currently done. We use classical U-statistic theory to analyze the variance reduction, and propose novel approximations with theoretical guarantees to ensure computational efficiency. We find empirically that U-statistic variance reduction can lead to modest to significant improvements in inference performance on a range of models, with little computational cost.