xin-icl-calibration-function-formula
IN premise — summaries/2026/08/24/xie-2021-icl-bayesian-sR-references.md
Created 2026-08-25T02:58:57+00:00
The multiclass calibration function used in the ICL theory is g(δ) = ½[(1−δ)log(1−δ) + (1+δ)log(1+δ)] for δ ∈ [0,1].
Summary
This formula defines the baseline cost function that the in-context learning theory uses to measure how much information is lost when the model's confidence across classes is imbalanced; the more the class probabilities drift away from uniform, the higher the calibration cost becomes. Because it is taken as a fixed starting point rather than derived from anything else, every downstream calibration bound or guarantee in the ICL framework ultimately traces back to this particular shape of the penalty.