将双（熔合）弧分离为多个弧

Question

在图论中，存在多个弧。但是，下图给出的是融合弧而不是多个弧。请问我该如何分离下面 tex 文件中的弧？请参阅下图以获取线索

\begin{figure}[H]
\centering
\begin{tikzpicture}[>=stealth',shorten >=1pt,auto,node distance=4.5cm,
   thick,main node/.style={circle,draw,font=\sffamily\Large\bfseries}]

\node[main node] (a)  {$v_1$};
\node[main node] (b)  [below of=a]{$v_2$};

\path
(a)      [->] edge node [pos=.5,above]  [left]{14} (b) 
(b)      [->]edge node [pos=.5,below][right] {30} (a);

\end{tikzpicture}
 \end{figure}

Answer 1

使用锚点：

\documentclass{article}
\usepackage{tikz}
\usetikzlibrary{arrows.meta}
\begin{document}

\begin{center}
    \begin{tikzpicture}[>=Stealth, shorten >=1pt, auto,node distance=4.5cm,
    thick,main node/.style={circle,draw,font=\sffamily\Large\bfseries}]

    \node[main node] (a)  {$v_1$};
    \node[main node] (b)  [below of=a]{$v_2$};

    \path (a.-70) [<-] edge node [right]{30} (b.70) 
    (b.110) [<-] edge node [left] {14} (a.-110);

    \end{tikzpicture}
\end{center}
\end{document}

Answer 2

您需要使用bend指令中的参数（带有方向和角度）edge-node来定义所需的弧

\documentclass{article}
\usepackage{pgfplots}
    \usetikzlibrary{arrows}
    \pgfplotsset{compat=1.15}

\begin{document}

\begin{figure}[h]
\centering
\begin{tikzpicture}[>=stealth',shorten >=1pt,auto,node distance=4.5cm,
  thick,main node/.style={circle,draw,font=\sffamily\Large\bfseries}]

\node[main node] (a)  {$v_1$};
\node[main node] (b)  [below of=a]{$v_2$};

\path
(a)[->] edge [bend right=45] node [pos=.5,above] [left]{14} (b) 
(b)[->] edge [bend right=45] node [pos=.5,below] [right]{30} (a);
\end{tikzpicture}
\end{figure}
\end{document}