Gated SAE
While L1 loss enforces sparsity, it can excessively reduce important features through shrinkage, making it difficult to properly represent the data.
- L1 penalty is only applied during the process of selecting (gating) which features to activate
- The degree of activation for selected neurons is determined without L1 penalty
In other words, feature activation remains sparse while preventing the L1 penalty from reducing the actual magnitude of values
Gated SAEs

anthropic analysis
Gated SAE
openai comparison against topk
Active Budget Can Kill Sensitivity
TopK SAE에서 활성화 feature 수인 \(k\)를 늘리면 reconstruction은 개선되지만, 희귀 feature의 의미적 안정성은 오히려 떨어진다.

Seonglae Cho