On a variety of tasks, the performance of neural networks predictably improves with training time, dataset size and model size across many orders of magnitude. This phenomenon is known as a neural scaling law. Of fundamental importance is the compute-optimal scaling law, which reports the performance as a function of units of compute when choosing model sizes optimally. We analyze a random feature model trained with gradient descent as a solvable model of network training and generalization. This reproduces many observations about neural scaling laws. First, our model makes a prediction about why the scaling of performance with training time and with model size have different power law exponents. Consequently, the theory predicts an asymmetric compute-optimal scaling rule where the number of training steps are increased faster than model parameters, consistent with recent empirical observations. Second, it has been observed that early in training, networks converge to their infinite-width dynamics at a rate $1/\textit{width}$ but at late time exhibit a rate $\textit{width}^{-c}$, where $c$ depends on the structure of the architecture and task. We show that our model exhibits this behavior. Lastly, our theory shows how the gap between training and test loss can gradually build up over time due to repeated reuse of data.

神经网络的表现在训练时间、数据集大小和模型大小上预测性地提高，这一现象被称为神经缩放定律，而计算最优缩放定律则是将性能作为计算单元函数以选择模型大小来报告的；研究表明，神经网络在训练早期以$1/	extit{width}$的速度收敛到无限宽度动力学，但在后期表现为$	extit{width}^{-c}$的速度，其中$c$取决于架构和任务的结构；此外，理论上显示了由于数据的重复重用，训练和测试损失之间的差距可以随时间逐渐增大。

神经缩放法则的动力学模型