tikzcd 环境：双箭头/平行箭头有错误？

Question

\documentclass{beamer}

\usepackage{tikz-cd}
\usetikzlibrary{matrix}

\begin{document}
\begin{frame}[fragile]

\begin{center}
\begin{tikzcd}[row sep=2.3cm, column sep = 
2.3cm]
A\arrow{r}{e}\arrow{d}[swap]{f} & B\arrow{r} 
{e1} \arrow{d}{g} &B1 \arrow{d}{g1}\\
C\arrow{r}[swap]{h} & D \arrow{r}[swap] 
{h}&D1\\
\end{tikzcd}
\end{center}

\end{frame}


\end{document}

在这里我想将每个箭头改为双箭头/平行箭头。我正在使用Leftrightarrow选项，例如，\arrow{r, Leftrightarrow}但出现错误。

如能提供任何帮助解决该问题，我们将不胜感激。

Answer 1

您可以使用该选项arrows=Leftrightarrow

\documentclass{beamer}

\usepackage{tikz-cd}
\usetikzlibrary{matrix}

\begin{document}
\begin{frame}[fragile]

\begin{center}
\begin{tikzcd}[
  row sep=2.3cm,
  column sep=2.3cm,
  arrows=Leftrightarrow,
]
A\arrow{r}{e}\arrow{d}[swap]{f} & B\arrow{r}
{e1} \arrow{d}{g} &B1 \arrow{d}{g1}\\
C\arrow{r}[swap]{h} & D \arrow{r}[swap]
{h}&D1\\
\end{tikzcd}
\end{center}

\end{frame}

\end{document}

“现代”语法更简单：

\begin{tikzcd}[
  row sep=2.3cm,
  column sep=2.3cm,
  arrows=Leftrightarrow,
]
A \arrow[r,"e"] \arrow[d,swap,"f"] &
B \arrow[r,"e1"] \arrow[d,"g"] &
B1 \arrow[d,"g1"]
\\
C \arrow[r,swap,"h"] & D \arrow[r,swap,"h"] &
D1
\end{tikzcd}

说只有左上角的箭头应该是Leftrightarrow；那么它可以输入为

\arrow[r,Leftrightarrow,"e"]

例如，

\begin{tikzcd}[
  row sep=2.3cm,
  column sep=2.3cm,
]
A \arrow[r,Leftrightarrow,"e"] \arrow[d,swap,"f"] &
B \arrow[r,"e1"] \arrow[d,"g"] &
B1 \arrow[d,"g1"]
\\
C \arrow[r,swap,"h"] & D \arrow[r,swap,"h"] &
D1
\end{tikzcd}

你会得到