[Tex/LaTex] Trees with only leaves in TikZ

foresttikz-pgftikz-treestrees

Following Roel's answer to How to write a tree with no (visible) root with TikZ? I attempted to visualise my Huffman-Code for "Tennessee", but it didn't turn out as I expected: enter image description here

My MWE:

\documentclass{standalone}
\usepackage{tikz}
\usepackage{tikz-qtree}
\usetikzlibrary{trees,arrows}
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
\begin{document}
    \begin{tikzpicture}[-,>=stealth',level/.style={sibling distance = 3cm, level distance = 1.5cm}] 
    \coordinate
            child {node [circle,draw] {E} edge from parent node[left] {\textcolor{red}{0}}} 
        child {edge from parent node[right]{\textcolor{red}{1}} 
            child {node [circle,draw] {S} edge from parent node[left] {\textcolor{red}{0}}}
            child {edge from parent node[right]{\textcolor{red}{1}}
                    child {node [circle,draw]{N} edge from parent node[left] {\textcolor{red}{0}}}
                    child {node [circle,draw]{T} edge from parent node[right] {\textcolor{red}{1}}}
                }
        };
\end{tikzpicture}
\end{document}

Obviously the numbering on the edges is not being level and more importantly, the edges are overlapping.

I experimented with removing the style, but that just leaves the tree narrower yet does not resolve the issue of the missing edge alignment.

Best Answer

You are supposed to put the edge from parent operation at the end of the corresponding child path declaration, like in the following :

\begin{tikzpicture}[-,>=stealth',level/.style={sibling distance = 3cm, level distance = 1.5cm}, leaf/.style={circle, draw}, label/.style={red},edge from parent path={(\tikzparentnode.south) -- (\tikzchildnode)}] 
    \coordinate[child anchor=south]
        child {node[leaf] {E} edge from parent node[left, label] {0}} 
        child {
            child {node [leaf] {S} edge from parent node[left, label] {0}}
            child {
                child {node [leaf]{N} edge from parent node[left, label] {0}}
                child {node [leaf]{T} edge from parent node[right, label] {1}}
                edge from parent node[right, label]{1}
            }
            edge from parent node[right, label]{1}
        };
\end{tikzpicture}

I added styles to get a cleaner code, and redefined edge from parent path to align the nodes (redefining child anchor and parent anchor should be enough, but there seems to be a bug with it in my version of Tikz)

Code

\documentclass[xcolor={table, dvipsnames}]{beamer}
\usepackage{forest}

\setbeamertemplate{navigation symbols}{} %Remove navigation bar
\tikzset{
    invisible/.style={opacity=0,text opacity=0},
    visible on/.style={alt=#1{}{invisible}},
    alt/.code args={<#1>#2#3}{%
      \alt<#1>{\pgfkeysalso{#2}}{\pgfkeysalso{#3}} % \pgfkeysalso doesn't change the path
    },
}
\forestset{
  visible on/.style={
    for tree={
      /tikz/visible on={#1},
      edge+={/tikz/visible on={#1}}}}}
\begin{document}
\begin{frame}[plain]{Same with forest}
    \begin{forest} baseline, for tree={draw,ellipse,align=center}
        [Picture root
            [First level class,fill=yellow,for children={visible on=<2->}
                [subcategorized,fill=gray]
                [another subcategory
                    [last node division,fill=gray]
                    [in two classes,fill=gray] 
                ] 
            ]
            [Another long category,fill=gray]
        ]    
    \end{forest}
\end{frame}
\end{document}

Output

enter image description here

[Tex/LaTex] Resolution trees in latex

Multiple parents to single child is done manually by adding edges to the nodes. So you build your tree as usual, and assign (easy to remember) node names to each or only to those nodes you need.

After the tree is done, inside the tikzpicture you can then draw the extra lines.

This is possible both with Tikz-qtree and with Tikz trees. I made a random edge just to show you how it's done (coloured in red). Feel free to modify as you need it.

Tikz-qtree

Output

enter image description here

Code

\documentclass[tikz, margin=10pt]{standalone}
\usepackage{tikz-qtree}
\usepackage{latexsym}

\begin{document}
\begin{tikzpicture}[grow'=up]
\Tree [.$\Box$ [. \node(m1){${\{m\}}$}; [.${\{a,m\}}$ ${\{3,4\}}$ ${\{5,6\}}$ ]
                           [.${\{ \neg a\}}$ ${\{8\}}$ ${\{7, \neg a\}}$ ] ]
                           [ [.\node(m2){${\{\neg m\}}$}; ${\{ \neg c\}}$ ${\{c, \neg m\}}$ ] ] ]

\draw[red] (m1.north) -- (m2.south);
\end{tikzpicture}
\end{document}

Tikz `trees`

Output

enter image description here

Code

\documentclass[tikz, margin=10pt]{standalone}
\usetikzlibrary{trees}

\tikzset{
    every node={circle,draw}
}


\begin{document}
\begin{tikzpicture}[level distance=1.5cm,
level 1/.style={sibling distance=3.5cm},
level 2/.style={sibling distance=1cm}]

\node (Root) {1}
    child {
    node (n2) {2} 
    child { node (n4) {4} }
    child { node (n5) {5} }
}
child {
    node (n3) {3}
    child { node (n6) {6} }
    child { node (n7) {7} }
};

\draw (n2) -- (n6);
\draw (n3) -- (n5);
\end{tikzpicture}
\end{document}

Best Answer

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[Tex/LaTex] Resolution trees in latex

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Tikz `trees`