如何通过分割来开始决策树？

Question

我正在尝试绘制一个简单的决策树，如图 1 所示https://besjournals.onlinelibrary.wiley.com/doi/full/10.1111/j.1365-2656.2008.01390.x

不幸的是，无论我尝试什么，我都无法调整第一个分支的兄弟距离。我对 tikz 还很陌生，所以非常感谢大家的帮助。最小工作代码示例：

\documentclass{minimal}
\usepackage[a4paper,margin=1cm,landscape]{geometry}
\usepackage{tikz}
\usetikzlibrary{positioning,shadows,arrows}
\begin{document}
\begin{center}
\begin{tikzpicture}[
    fact/.style={rectangle, draw=blue, rounded corners=1mm, fill=white, %drop shadow,
        text centered, anchor=north, text=black},
    state/.style={circle, draw=orange, fill=white, %circular drop shadow,
        text centered, anchor=north, text=black},
    leaf/.style={circle, draw=red, fill=white, %circular drop shadow,
        text centered, anchor=north, text=black},
    level distance=1cm, growth parent anchor=south,
]
\node (State00) [state] {$x_{1}$}
child{ 
    node (Fact01) [fact] {$\leq z_1$}
    child{ [sibling distance=4cm]
        node (State01) [state] {$x_2$} 
        child{ 
            node (Fact02) [fact] {$\leq z_1$}
            child{ [sibling distance=2cm]
                node (State02) [leaf] {$y_1$}
                }
            }       
        child{
            node (Fact03) [fact] {$> z_1$}
            child{
                node (State03) [leaf] {$y_2$}
                }
            }
        }
    node (Fact04) [fact] {$> z_1$}
    child{ [sibling distance=3cm]
        node (State04) [state] {$x_1$}
        child{ 
            node (Fact05) [fact] {$\leq z_3$}
            child{
                node (State05) [leaf] {$y_3$} 
                }
            }
        child{
            node (Fact06) [fact] {$> z_3$}
            child{ [sibling distance=3cm]
                node (State06) [state] {$x_2$}
                child{
                    node (Fact07) [fact] {$\leq z_4$}
                    child{ 
                        node (State07) [leaf] {$y_4$}
                        }
                    }
                child{
                    node (Fact08) [fact] {$> z_4$}
                    child{
                        node (State08) [leaf] {$y_5$}
                        }
                    }
                }
            }
        }
    }
;

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

我的输出总是像这样：

Answer 1

我怀疑您正在寻找以下树状图：

我必须承认我迷失在你的代码中。所以我建议（就我而言）使用forest包的简单解决方案：

\documentclass[tikz,margin=3mm]{standalone}
\usepackage{forest}

\begin{document}
\begin{forest}
for tree = {
fact/.style={rectangle, draw=blue, rounded corners=1mm,
             text centered, text=black},
        circle, 
        draw=orange, 
        text centered, 
        text=black,
        s sep+=4pt,
        l sep=8mm
            }
[$x_1$
    [$\leq z_1$,fact
        [$x_1$
            [$\leq z_1$,fact
                [$y_1$]
            ]
            [$\leq z_2$,fact
                [$y_2$]
            ]
            [$>z_3$,fact
                [$x_2$
                    [$\leq z_4$,fact
                        [$y_4$]
                    ]
                    [$>z_4$,fact
                        [$y_5$]
                    ]
                ]
            ]
            [$>z_1$,fact
                [$y_5$]
            ]
        ]
    ]
]
;
\end{forest}
\end{document}