论文标题
通过有限差分评分匹配生成模型的有效学习
Efficient Learning of Generative Models via Finite-Difference Score Matching
论文作者
论文摘要
几种机器学习应用程序涉及在训练过程中优化高阶导数(例如,梯度的梯度),即使自动差异也可能在记忆和计算方面都很昂贵。作为生成建模的典型示例,得分匹配(SM)涉及Hessian痕迹的优化。为了提高计算效率,我们根据方向衍生剂重写SM目标及其变体,并提出了一种通用策略,以有效地近似于有限的差异(FD)。我们的近似值仅涉及功能评估,可以并行执行,而无需梯度计算。因此,它降低了总计算成本,同时也提高了数值稳定性。我们通过将SM目标的变体重新定义为FD形式来提供两种实例。从经验上讲,我们证明我们的方法产生的结果可与基于梯度的同行相媲美,同时在计算上更有效。
Several machine learning applications involve the optimization of higher-order derivatives (e.g., gradients of gradients) during training, which can be expensive in respect to memory and computation even with automatic differentiation. As a typical example in generative modeling, score matching (SM) involves the optimization of the trace of a Hessian. To improve computing efficiency, we rewrite the SM objective and its variants in terms of directional derivatives, and present a generic strategy to efficiently approximate any-order directional derivative with finite difference (FD). Our approximation only involves function evaluations, which can be executed in parallel, and no gradient computations. Thus, it reduces the total computational cost while also improving numerical stability. We provide two instantiations by reformulating variants of SM objectives into the FD forms. Empirically, we demonstrate that our methods produce results comparable to the gradient-based counterparts while being much more computationally efficient.