Objective. Fit a single ReLU-shaped hinge (“ReLU-1”) to approximate the shape FAct converges to, and see whether that much cheaper, piecewise-linear stand-in captures FAct’s advantage.
| GPU(s) | mixed: A100 / L4 (a host-effect check between them found p=0.66, no detectable difference) |
| Dataset(s) | FashionMNIST, CIFAR-10, CIFAR-100 |
| Model | ViT-100K (part of the 12-activation zoo, Experiment-63) |

Result summary
- 5 seeds × 3 datasets, the one-hinge fit: FMNIST 0.9065, CIFAR-10 0.7456, CIFAR-100 0.4733.
- Beats GELU, SiLU, and Mish on all three datasets.
- Ties plain ReLU on FMNIST and CIFAR-10, but beats it — and beats trainable EFAct — on CIFAR-100.
- An A100-vs-L4 host-effect check found p=0.66: no detectable difference from which GPU ran the job.
Insights
- A single well-placed hinge captures a meaningful fraction of what the full 5-coefficient Fourier curve is doing — you don’t need the periodic machinery to get most of the benefit on the easier datasets, though CIFAR-100 is where the fuller curve starts to matter.