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AI by Hand ✍️

Log-Sum-Exp

Activation series: 9 of 12

Prof. Tom Yeh's avatar
Prof. Tom Yeh
May 11, 2026
∙ Paid

Activation Series:

  1. Softmax

  2. Sigmoid

  3. Tanh

  4. ReLU

  5. Leaky ReLU

  6. ELU

  7. SiLU

  8. GELU

  9. Log-Sum-Exp

  10. Softplus

  11. GLU

  12. SwiGLU

Log-sum-exp (LSE) is the smooth maximum function: the smooth-and-differentiable cousin of max. It shows up at the heart of softmax, cross-entropy loss, and any computation that combines values on a log scale.

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