tikz 树中的分支方向

Question

以下代码

\documentclass[border=10pt,varwidth]{standalone}
\usepackage{tikz}
\usetikzlibrary{calc, shapes, backgrounds}
\usepackage{amsmath, amssymb}    
\begin{figure*}
   \centering
 \tikzset{
    head/.style = {label = center:\textsf{\Large H}},
    tail/.style = {label = center:\textsf{\Large T}}
 }
\begin{tikzpicture}[
    scale = 1.5, transform shape, thick,
    every node/.style = {draw, circle, minimum size = 10mm},
    grow = down,  % alignment of characters
    level 1/.style = {sibling distance=4cm},
    level 2/.style = {sibling distance=3cm}, 
    level 3/.style = {sibling distance=2cm}, 
    level distance = 1.25cm
  ]
 \node[circle, draw, line width = 1pt,
      minimum size = 10mm, inner sep = 0mm, font = \sffamily\large] (Start)    
  {root} 
  child { node [head] (A) {}
     child { node [head] (B) {}}
     child { node [tail] (C) {}}
   }
   child {   node [tail] (D) {}
      child { node [head] (E) {}}
     child { node [tail] (F) {}}
   };


   % Labels
   \begin{scope}[nodes = {draw = none}]
      \path (Start) -- (A) node [near start, left]  {$0.5$};
      \path (A)     -- (B) node [near start, left]  {$0.5$};
      \path (A)     -- (C) node [near start, right] {$0.5$};
      \path (Start) -- (D) node [near start, right] {$0.5$};
      \path (D)     -- (E) node [near start, left]  {$0.5$};
      \path (D)     -- (F) node [near start, right] {$0.5$};
   \end{scope}
 \end{tikzpicture}
\end{figure*}

产生以下输出

如何修改代码以获得某些节点的分支的不同方向？例如，如下所示：

此外，如果我想在不同的边上写不同的标签怎么办？例如在分支 TT 上写 0.6 而不是 0.5？

Answer 1

与森林相对简单:-)：

• 第一张图片：

  \documentclass[border=10pt]{standalone}
  \usepackage[edges]{forest}
  
  \begin{document}
  \begin{forest}
      for tree={
          circle,
          draw, minimum size=8mm, font=\sffamily\Large, inner sep=1pt,
          l sep = 18pt,
          s sep =  6pt,
  % labels on edges
      EL/.style 2 args={
        edge label/.wrap value={node[midway, font=\sffamily\footnotesize, #1] {#2}},
            },
              }, % end for tree
  [root
      [H,edge label=left
      [H,EL={left}{0.1}
          [H,EL={left}{0.3}]
          [T,EL={right}{0.7}]
      ]
      [T,EL={right}{0.9},
         %calign=first
          [H,EL={left}{0.6}]
          [T,EL={right}{0.4}]
      ]
  ]
   \end{forest}
   \end{document}
  

• 第二张图片：

  \documentclass[border=10pt]{standalone}
  \usepackage[edges]{forest}
  
  \begin{document}
  \begin{forest}
      for tree={
          circle,
          draw, minimum size=8mm, font=\sffamily\Large, inner sep=1pt,
          l sep = 18pt,
          s sep =  6pt,
  % labels on edges
      EL/.style 2 args={
        edge label/.wrap value={node[midway, font=\sffamily\footnotesize, #1] {#2}},
            },
              }, % end for tree
      [H,EL={left}{0.1}
          [H,EL={left}{0.5}]
          [T,EL={right}{0.5}]
      ]
      [T,EL={right}{0.9},
         calign=first      % change branch direction
          [H,EL={left}{0.5}]
          [T,EL={right}{0.5}]
      ]
  ]
   \end{forest}
   \end{document}
  

编辑： 在这两种情况下，现在都认为每个分支标签可以具有不同的值。