tikz 图的边缘跳过“代”

Question

我有一棵三层的树，想从第 1 层到第 3 层绘制边。我使用的是“从父节点开始的边”，但想使用类似“到祖父节点的边”之类的东西。到目前为止，我得到的结果呈 Y 形，这还算不错，但我更喜欢两条直线而不是“祖父节点”。

有什么办法可以得到“祖父母”选项吗？

\documentclass{article}

\usepackage{amssymb, amsmath, amstext}
\usepackage{tikz}

\begin{document}
\begin{tikzpicture}[scale=1]
\tikzstyle{every node}=[circle,draw,inner sep=1pt]
\tikzstyle{level 1}=[sibling distance=60mm]
\tikzstyle{level 2}=[sibling distance=35mm,set style={{every node}+=[circle]}]
\tikzstyle{level 3}=[sibling distance=20mm,set style={{every node}+=[circle]}]

\node{}[grow'=south]
child {node{$\overline{G}$}
    child{node[label={right:}]{$\overline{A}$}
        child{node[label={right:}]{$\overline{E}$}
                edge from parent        
                node[ right,draw=none,fill=none]{~$1$}
            }
            edge from parent        
            node[ right,draw=none,fill=none]{~$0.35$}
        }
    child{node[label={right:}]{$A$}
        child{node[label={right:}]{$\overline{E}$}
                edge from parent        
                node[ right,draw=none,fill=none]{~$0.7$}
            }
        child{node[label={right:}]{E}
                edge from parent        
                node[ left,draw=none,fill=none]{$0.3$~~}
            }
            edge from parent        
            node[ left,draw=none,fill=none]{$0.65$~~}
        }   
    edge from parent        
    node[above right,draw=none,fill=none]{$0.87$}
}
child {node[label={}]{$G$}
    child{
            child{node[label={below:}]{$\overline{E}$}
                    edge from parent        
                    node[ right,draw=none,fill=none]{~$0.996$}
                }
            child{node[label={right:}]{$E$}
                    edge from parent        
                    node[ left,draw=none,fill=none]{$0.004$~~}
                }
                edge from parent
                %node[ left,draw=none,fill=none]{$0.65$~~}
            }   
        edge from parent        
    node[above left,draw=none,fill=none]{$0.13$}
}
;
\end{tikzpicture}

\end{document}

Answer 1

仅供比较，这里是使用 的树forest，它提供了tier选项。

\documentclass{article}

\usepackage{forest}

\begin{document}

\begin{forest}
for tree={
    draw, circle, inner sep=1pt, l sep=7mm, s sep=1cm,
    if n children=0{tier=leaf}{}
}
[
    [$G$, edge label={node[midway, above left]{0.13}}
        [$E$, edge label={node[midway, left]{0.004}}]
        [$\overline{E}$, edge label={node[midway, right]{0.996}}]
    ]
    [$\overline{G}$, edge label={node[midway, above right]{0.87}}
        [$A$, edge label={node[midway, left]{0.65}}
            [$E$, edge label={node[midway, left]{0.3}}]
            [$\overline{E}$, edge label={node[midway, right]{0.7}}]
        ]
        [$\overline{A}$, edge label={node[midway, right]{.35}}
            [$\overline{E}$, edge label={node[midway, right]{1}}]
        ]
    ]
]
\end{forest}

\end{document}