How do I draw a B+ tree in latex?

Question

Is there some way to draw a B+ tree in latex? It would look something like the picture below (ignoring the animations)

Animation linked here: https://i.stack.imgur.com/JRcmY.gif

Screenshot of the start of the animation:

Answer 1

I would do this in TikZ. Section 18.1 of the version 2.10 manual shows how to make trees. The nodes on the trees are a little nonstandard, but perhaps section 16.3 on multi-part nodes would be helpful.

Here's a quick mockup:

\documentclass{article}
\usepackage{tikz}
\usetikzlibrary{shapes}
\begin{document}
\begin{center}
\begin{tikzpicture}
\tikzstyle{bplus}=[rectangle split, rectangle split horizontal,rectangle split ignore empty parts,draw]
\tikzstyle{every node}=[bplus]
\tikzstyle{level 1}=[sibling distance=60mm]
\tikzstyle{level 2}=[sibling distance=15mm]
\node {15} [->]
  child {node {3 \nodepart{two} 7}
    child {node {1 \nodepart{two} 2}}
    child {node {4 \nodepart{two} 6}}
    child {node {8 \nodepart{two} 9}}    
  } 
  child {node {21 \nodepart{two} 28 \nodepart{three} 32 \nodepart{four} 50}
    child {node {17 \nodepart{two} 20}}
    child {node {22 \nodepart{two} 25}}
    child {node {28 \nodepart{two} 30}}    
    child[sibling distance=25mm] {node {34 \nodepart{two} 38 \nodepart{three} 44 \nodepart{four} 47}}    
    child[sibling distance=25mm] {node {53 \nodepart{two} 54 \nodepart{three} 60 \nodepart{four} 88}}    
  }
;\end{tikzpicture}
\end{center}

\end{document}

It's going to be more work to get the vertical lines doubled like in your example. The code for the rectangle split shape may need to be altered.

Answer 2

I found an .sty file by Prof. Wei Wang from University of New South Wales which seems pretty nice:

http://www.cse.unsw.edu.au/~weiw/tools.html

\NeedsTeXFormat{LaTeX2e}
\ProvidesPackage{weiwBTree}
\typeout{Document Style `weiw_BTree - Support drawing B+-Tree (ver 0.999)}

\RequirePackage{tikz}
\RequirePackage{ifthen}

% use libraries
\usetikzlibrary{arrows,shapes,snakes,matrix}


%% global declaration
\tikzstyle{btreeptr} = [draw, semithick, fill=blue!50, minimum height=2em]
\tikzstyle{btreeval} = [draw, semithick, fill=yellow!30, minimum size=2em]
\tikzstyle{btreevale} = [draw,semithick, fill=green!30, minimum size=2em]
\tikzstyle{btlink} = [draw, semithick, ->, >=triangle 45]

%% macro
%% helper macros
\newcommand{\suppressemptystr}[1]{% leave blank for entries in leaf nodes
  \ifthenelse{\equal{#1}{}}%
  {%
    \relax%
  }%
  % Else
  {%
    #1\textsuperscript{*}%
  }%
}%

\newcommand{\xyshift}[3]{% help to place the nodes
  \begin{scope}[xshift=#1, yshift=#2]
    #3
  \end{scope}%
}

%% Common btree macros
\newcommand{\btreelink}[2]{% #1: src node; #2: dest node; 
  \draw[btlink] ([yshift=3pt] #1.south) -- (#2-b.north);
}

\newcommand{\btreelinknorth}[2]{% #1: src node; #2: dest node; 
  \draw[btlink] ([yshift=3pt] #1.south) -- (#2.north);
}

\newcommand{\btreetriangle}[2]{% #1: node name; #2 text inside
  \node[anchor=north, regular polygon, regular polygon sides=3, draw] (#1) {#2};
}

%%======================================================================
%% btree with capacity = 4
\newcommand{\btreeinodefour}[5]{%
  \matrix [ampersand replacement=\&] (#1)
  {
    \node[btreeptr] (#1-1) {\vphantom{1}}; \& \node[btreeval] (#1-a) {#2}; \&
    \node[btreeptr] (#1-2) {\vphantom{1}}; \& \node[btreeval] (#1-b) {#3}; \&
    \node[btreeptr] (#1-3) {\vphantom{1}}; \& \node[btreeval] (#1-c) {#4}; \&
    \node[btreeptr] (#1-4) {\vphantom{1}}; \& \node[btreeval] (#1-d) {#5}; \&
    \node[btreeptr] (#1-5) {\vphantom{1}}; \\
  };
}
\newcommand{\btreelnodefour}[5]{%
  \matrix [ampersand replacement=\&, outer sep=0pt, matrix anchor=north] (#1)
  {
    \node[btreevale] (#1-a) {\suppressemptystr{#2}}; \&
    \node[btreevale] (#1-b) {\suppressemptystr{#3}}; \&
    \node[btreevale] (#1-c) {\suppressemptystr{#4}}; \&
    \node[btreevale] (#1-d) {\suppressemptystr{#5}}; \\
  };
}

%%======================================================================
%% btree with capacity = 3
\newcommand{\btreeinodethree}[4]{%
  \matrix [ampersand replacement=\&] (#1)
  {
    \node[btreeptr] (#1-1) {\vphantom{1}}; \& \node[btreeval] (#1-a) {#2}; \&
    \node[btreeptr] (#1-2) {\vphantom{1}}; \& \node[btreeval] (#1-b) {#3}; \&
    \node[btreeptr] (#1-3) {\vphantom{1}}; \& \node[btreeval] (#1-c) {#4}; \&
    \node[btreeptr] (#1-4) {\vphantom{1}}; \\
  };
}
\newcommand{\btreelnodethree}[4]{%
  \matrix [ampersand replacement=\&, outer sep=0pt, matrix anchor=north] (#1)
  {
    \node[btreevale] (#1-a) {\suppressemptystr{#2}}; \&
    \node[btreevale] (#1-b) {\suppressemptystr{#3}}; \&
    \node[btreevale] (#1-c) {\suppressemptystr{#4}}; \\
  };
}
%%======================================================================






%% simple example
%  \begin{center}
%    \scalebox{0.7}{
%      \begin{tikzpicture}
%        % 
%        \btreeinodefour{root}{13}{17}{24}{30};
%        \xyshift{-40mm}{-20mm}{\btreelnodefour{n1}{2}{3}{5}{7}}
%        \xyshift{-0mm}{-20mm}{\btreelnodefour{n2}{14}{16}{}{}}
%        \xyshift{40mm}{-20mm}{\btreelnodefour{n3}{19}{20}{22}{}}
%        \xyshift{80mm}{-20mm}{\btreelnodefour{n4}{24}{27}{29}{}}
%        \xyshift{120mm}{-20mm}{\btreelnodefour{n5}{33}{34}{38}{39}}
%        %
%        \foreach \x in {1,2,...,5} { \btreelink{root-\x}{n\x} }
%      \end{tikzpicture}
%    }
%  \end{center}

Answer 3

http://tug.org/PSTricks/main.cgi?file=pst-tree/pst-tree#binary can be modified to your needs