Objective. Round out the ImageNet-1K comparison with the fixed activations everyone actually reaches for in practice — ReLU, LeakyReLU, SiLU — under the exact same recipe as the FAct/GELU runs.
| GPU(s) | H200 |
| Dataset(s) | ImageNet-1K |
| Model | ViT, depth 6 (embed_dim 384) |

Result summary
- ReLU and LeakyReLU tie at 0.609 test top-1.
- SiLU reached 0.515 best-so-far at epoch 42/100 before this arm was left in progress — not a finished number.
- Against the same table’s GELU (0.625) and trainable FAct (0.6512): FAct leads every fixed activation tried.
- A documentation slip surfaced along the way: the “identical parameter count” claim in the write-up was wrong — FAct actually carries +5 parameters (its shared coefficients), and
train_one()was found to returnresult.jsonrather than write it to disk directly.
Insights
- None of the standard fixed activations close the gap to FAct — the comparison isn’t “FAct vs one arbitrary baseline,” it’s FAct ahead of the whole familiar shortlist.
- The SiLU arm was never watched by a monitoring script and nobody caught it stalling — a small operational lesson repeated elsewhere in this catalog: an unattended long run needs a watchdog, not just a launch command.