tikz 中节点链接上的标签

Question

虽然@cfr 为我的帖子提供了一个很好的解决方案这里，当我将代码插入主文档时，我遇到了问题，尽管它可以作为独立文档正常工作。它给出了错误：！\pgfmath@expression 定义中的参数编号非法，表明错误发生在 \end{forest}。虽然 forest 似乎更适合树形图，但我发现它非常困难。我需要一些时间才能解决 forest 包的问题。因此，我在 tikz 中重现了我的 mwe，只有树形图和我想要标签的位置（如我的代码中注释掉的那样）。

\documentclass[12pt]{report}
\usepackage{tikz}

\begin{document}
\begin{tikzpicture}[inner sep=1.5pt]
\node (10) {z}
child { node {x}
child { node {s}}
   child { node {t}}}
child { node {y}
child { node {s}}
child { node {t}}}
;
%    \node      (from z to x) {$\frac{\partial z}{\partial x}$};
%    \node      (from z to y) {$\frac{\partial z}{\partial y}$};
%    \node      (from x to s) {$\frac{\partial x}{\partial s}$};
%    \node      (from x to t) {$\frac{\partial x}{\partial t}$};
%    \node      (from y to s) {$\frac{\partial y}{\partial s}$};
%    \node      (from y to t) {$\frac{\partial y}{\partial t}$};

\end{tikzpicture}
\end{document}

Answer 1

仅适用于 TikZ 的建议：

\documentclass[12pt]{report}
\usepackage{tikz}
\begin{document}
\begin{tikzpicture}[inner sep=1.5pt]
\node (10) {z}
  [ auto,
    sibling distance=2.4cm,
    level distance=2cm,
    level 2/.append style={
      sibling distance=1.8cm,
      level distance=1.5cm
    },
    edge from parent/.append style={nodes={pos=.6}}
  ]
  child { node {x}
    child { node {s}
      edge from parent node[swap]{$\frac{\partial x}{\partial s}$}
    }
    child { node {t}
      edge from parent node{$\frac{\partial x}{\partial t}$}
    }
    edge from parent node[swap]{$\frac{\partial z}{\partial x}$}
  }
  child { node {y}
    child { node {s}
      edge from parent node[swap]{$\frac{\partial y}{\partial s}$}
    }
    child { node {t}
      edge from parent node{$\frac{\partial y}{\partial t}$}
    }
    edge from parent node{$\frac{\partial z}{\partial y}$}
}
;
\end{tikzpicture}
\end{document}