发现训练数据越多,随机初始化越难比梯度下降泛化好
Revisiting the Volume Hypothesis
- 用物理模拟方法估算权重空间中泛化好坏区域的体积分布
- 在中等数据量下,梯度下降的泛化优势显著,数据多时优势减弱
- 解释了为何不同实验结果看似矛盾,揭示体积假说的适用边界
现代深度神经网络参数远超拟合训练数据所需,却仍具优异泛化能力。主流解释是随机梯度下降(SGD)的隐式偏差,另一观点认为:在低损失区域,能产生良好泛化的权重盆地占据更大空间,故SGD更易落入此类区域。近期实验对此提出矛盾证据:随机采样权重至零训练误差时泛化差,但分子动力学密度估计支持体积假说。我们发现这些实验处于不同数据规模,通过复本交换王-兰道算法,在二值网络中联合估计训练与测试精度的态密度。在多个架构和数据集上,发现梯度学习相比随机采样的泛化优势随训练数据量增加而减弱,从而调和了上述矛盾。
原文摘要 · Abstract (English)
Modern deep neural networks often contain far more parameters than needed to fit their training data, yet they achieve impressive generalization. A common explanation for this success is the implicit bias of stochastic gradient descent (SGD). An alternative volume hypothesis posits that, within low training-loss regions, loss-landscape basins leading to strong generalization occupy much larger regions of weight space than basins that generalize poorly, and therefore SGD is simply more likely to land in the former. Recent experimental explorations of this idea present seemingly contradictory results. While in one set of experiments randomly sampling the network weights until achieving zero training error yielded poor generalization, molecular dynamics density estimates supported the volume hypothesis. We observe that these experiments were performed at different dataset size regimes, and explore an intermediate regime using the Replica Exchange Wang-Landau algorithm to estimate the joint density of states over training and test accuracies in binary networks. Across several architectures and datasets, we show that the generalization advantage of gradient learning over random sampling training generally diminishes as the training data size grows, suggesting a resolution of the paradox.
Thank you to arXiv for use of its open access interoperability. PaperDance 不是 arXiv 官方产品;中文卡片由大模型生成,请以原文为准。