我正在尝试向路径添加一些标签，但我无法计算出已使用graphs和创建的现有路径的坐标matrix。我找到了一种解决方法，即对坐标进行硬编码并添加新标签。下面的代码是 MWE，我后来添加的标签位于注释“新标签”之后（见下面的代码）。
问题是，如果我改变角度out=XXX、in=XXX和，这就会中断looseness=XXX。我一直在寻找是否可以从现有节点建立坐标。
谢谢
这是我的 MWE：
\documentclass{standalone}
\usepackage{tikz}
\usetikzlibrary{%
arrows.meta,
calc,
graphs,
matrix,
positioning,
}
\begin{document}
\begin{tikzpicture}
\matrix (bn) [matrix of nodes, column sep=14mm, row sep=1mm, nodes={draw, circle, fill=white, very thick, minimum width=8mm}]
{
1 & 2 & 3 & 4 & 5 & 6 & 7 & 8\\
};
\graph[edges={>=Latex, semithick, color=black, out=30, in=155}] {
(bn-1-1) -> (bn-1-2) -> (bn-1-3) -> (bn-1-4) -> (bn-1-5) -> (bn-1-6) -> (bn-1-7) -> (bn-1-8)
};
\graph[edges={>=Latex, semithick, color=black, out=210, in=335}] {
(bn-1-8) -> (bn-1-7) -> (bn-1-6) -> (bn-1-5) -> (bn-1-4) -> (bn-1-3) -> (bn-1-2) -> (bn-1-1)
};
\foreach \x in {1,...,8}
\path[->,>=Latex]
(bn-1-\x) edge [out=110,in=70,looseness=12] node[above] {} (bn-1-\x);
% New labels
\node (pnq) at ([yshift=7.5mm]$(bn-1-3)!0.5!(bn-1-4)$) {$p(1-q)$};
\node (npq) at ([yshift=-7.5mm]$(bn-1-3)!0.5!(bn-1-2)$) {$q(1-p)$};
\node (npq) at ([yshift=16.5mm]$(bn-1-3)!0.5!(bn-1-3)$) {$pq$};
\end{tikzpicture}
\end{document}
图片：
答案1
\graph[edges={>=Latex, semithick, color=black, out=30, in=155}] {
(bn-1-1) ->[ pos=0.48,edge label=\scriptsize A] (bn-1-2) -> (bn-1-3) -> (bn-1-4) -> (bn-1-5) -> (bn-1-6) -> (bn-1-7) -> (bn-1-8)
};
\graph[edges={>=Latex, semithick, color=black, out=210, in=335}] {
(bn-1-8) -> (bn-1-7) -> (bn-1-6) -> (bn-1-5) -> (bn-1-4) -> (bn-1-3) -> (bn-1-2) ->[pos=0.48,edge label=\scriptsize B] (bn-1-1)
};
以及循环
\foreach \x in {1,...,8}
\path[->,>=Latex]
(bn-1-\x) edge [out=110,in=70,looseness=12] node[yshift=-5pt, above, label=\scriptsize bn-1-\x] {} (bn-1-\x);
平均能量损失
\documentclass{standalone}
\usepackage{tikz}
\usetikzlibrary{%
arrows.meta,
calc,
graphs,
matrix,
positioning,
}
\begin{document}
\begin{tikzpicture}
\matrix (bn) [matrix of nodes, column sep=14mm, row sep=1mm, nodes={draw, circle, fill=white, very thick, minimum width=8mm}]
{
1 & 2 & 3 & 4 & 5 & 6 & 7 & 8\\
};
\graph[edges={>=Latex, semithick, color=black, out=30, in=155}] {
(bn-1-1) ->[ pos=0.48,edge label=\scriptsize A] (bn-1-2) -> (bn-1-3) -> (bn-1-4) -> (bn-1-5) -> (bn-1-6) -> (bn-1-7) -> (bn-1-8)
};
\graph[edges={>=Latex, semithick, color=black, out=210, in=335}] {
(bn-1-8) -> (bn-1-7) -> (bn-1-6) -> (bn-1-5) -> (bn-1-4) -> (bn-1-3) -> (bn-1-2) ->[pos=0.48,edge label=\scriptsize B] (bn-1-1)
};
\foreach \x in {1,...,8}
\path[->,>=Latex]
(bn-1-\x) edge [out=110,in=70,looseness=12] node[yshift=-5pt, above, label=\scriptsize bn-1-\x] {} (bn-1-\x);
% New labels
% \node (pnq) at ([yshift=7.5mm]$(bn-1-3)!0.5!(bn-1-4)$) {$p(1-q)$};
% \node (npq) at ([yshift=-7.5mm]$(bn-1-3)!0.5!(bn-1-2)$) {$q(1-p)$};
% \node (npq) at ([yshift=16.5mm]$(bn-1-3)!0.5!(bn-1-3)$) {$pq$};
\end{tikzpicture}
\end{document}
编辑将标签添加到单循环
平均能量损失
\documentclass{standalone}
\usepackage{tikz}
\usetikzlibrary{%
arrows.meta,
calc,
graphs,
matrix,
positioning,
}
\begin{document}
\begin{tikzpicture}
\matrix (bn) [matrix of nodes, column sep=14mm, row sep=1mm, nodes={draw, circle, fill=white, very thick, minimum width=8mm}]
{
1 & 2 & 3 & 4 & 5 & 6 & 7 & 8\\
};
\graph[edges={>=Latex, semithick, color=black, out=30, in=155}] {
(bn-1-1) ->[ pos=0.48,edge label=\scriptsize A] (bn-1-2) -> (bn-1-3) -> (bn-1-4) -> (bn-1-5) -> (bn-1-6) -> (bn-1-7) -> (bn-1-8)
};
\graph[edges={>=Latex, semithick, color=black, out=210, in=335}] {
(bn-1-8) -> (bn-1-7) -> (bn-1-6) -> (bn-1-5) -> (bn-1-4) -> (bn-1-3) -> (bn-1-2) ->[pos=0.48,edge label=\scriptsize B] (bn-1-1)
};
\foreach \x in {1,2,4,5,6,7,8}
\path[->,>=Latex]
(bn-1-\x) edge [out=110,in=70,looseness=12] node[] {} (bn-1-\x);
\foreach \x in {3}
\path[->,>=Latex]
(bn-1-\x) edge [out=110,in=70,looseness=12] node[yshift=-5pt, above, label=\scriptsize pq] {} (bn-1-\x);
\end{tikzpicture}
\end{document}
