% Golden example -- a scale rewrite that must be seen, not just aligned.
%   ../scripts/build.sh rewrite-cancel.tex
\documentclass[border=10pt]{standalone}
\usepackage[cjk]{superderive}

\begin{document}
\begin{tikzpicture}
\sdstage{D1}{缩放来自方差，不是装饰}
\sdrow{R1}
  \sdstep[role=rewrite]{s1}{QK^{\top}}{QK^{\top}/\sqrt{d_k}}
  \sdreason{s1}{§3.2.1，避免 softmax 饱和}
\sdrowend
\sdbbox{all}
\sdtopformula{F}{$\mathrm{Attention}(Q,K,V)=\mathrm{softmax}(QK^{\top}/\sqrt{d_k})V$}
\sdmeaningbox{mb}{120mm}{all}
  {点积方差随 $d_k$ 线性涨}
  {缩放是改写，不是新算子}
  {没有缩放，softmax 进饱和区，梯度消失}
\end{tikzpicture}
\end{document}