# How to put an algorithm and a tikz drawing (objects of different type) side-by-side in the same float environment?

I am trying to put an algorithm and a tikz' drawing side-by-side inside a figure environment. I am aware of this question but I would like to have a single caption for them. For instance, in the text, Figure 1a would refer to the algorithm while Figure 1b would refer to the tikz' drawing.

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How do you set the algorithm? –  egreg Jan 6 '12 at 16:12
Use the package subcaption. –  Marco Daniel Jan 6 '12 at 16:13
@egreg: I have tried using nested \minipage...\begin{algorithm}...\begin{algorithmic}<algorithm here>...\end..\end..\end, nested \minipage...\begin{algorithmic}<algorithm here>...\end..\end and just \begin{algorithmic}<algorithm here>...\end directly inside the \subfloat (obviously with the correct syntax) but none of them worked out. –  freitass Jan 6 '12 at 16:16
@MarcoDaniel: I have already looked at it, but couldn't figure out how to make that work. –  freitass Jan 6 '12 at 16:19
@freitass: I edited slightly the title to make it more generic. I hope that's ok with you. –  Count Zero Jan 6 '12 at 17:44

I recommend the using of the subcaption package. It works well with caption (same author, thanks Axel).

\documentclass{article}
\usepackage{algorithm}% http://ctan.org/pkg/algorithm
\usepackage{algpseudocode}% http://ctan.org/pkg/algorithmicx

\usepackage{caption}
\usepackage{subcaption}
\usepackage{tikz}
\begin{document}
\section{foo}
Text

\begin{figure}[!ht]
\begin{subfigure}[b]{.5\linewidth}
\centering
\begin{algorithmic}[1]
\Procedure{Euclid}{$a,b$}\Comment{The g.c.d. of a and b}
\State $r\gets a\bmod b$
\While{$r\not=0$}\Comment{We have the answer if r is 0}
\State $a\gets b$
\State $b\gets r$
\State $r\gets a\bmod b$
\EndWhile\label{euclidendwhile}
\State \textbf{return} $b$\Comment{The gcd is b}
\EndProcedure
\end{algorithmic}

\caption{Algorithm}\label{fig:alg}
\end{subfigure}%
\begin{subfigure}[b]{.5\linewidth}
\centering
\tikz\draw [fill=red!20] (0,0) rectangle (3,2);
\caption{tikz}\label{fig:tikz}
\end{subfigure}
\caption{Both}\label{fig:both}
\end{figure}

Text \ref{fig:alg} and \ref{fig:tikz} and \ref{fig:both}

\end{document}


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That is just what I needed. Thank you very much! Thank also to the algpseudocode package. I tried the same with the algorithmic package and it didn't work. –  freitass Jan 6 '12 at 17:04

Just don't enclose algorithmic in the algorithm environment, but rather in a minipage; here I've used varwidth to get the exact width.

\documentclass{article}
\usepackage[demo]{graphicx}
\usepackage{varwidth,algorithmic}
\begin{document}
\begin{figure}
\centering
\begin{varwidth}[c]{\textwidth}
\begin{algorithmic}
\REQUIRE $n \geq 0 \vee x \neq 0$
\ENSURE $y = x^n$
\STATE $y \leftarrow 1$
\IF{$n < 0$}
\STATE $X \leftarrow 1 / x$
\STATE $N \leftarrow -n$
\ELSE
\STATE $X \leftarrow x$
\STATE $N \leftarrow n$
\ENDIF
\WHILE{$N \neq 0$}
\IF{$N$ is even}
\STATE $X \leftarrow X \times X$
\STATE $N \leftarrow N / 2$
\ELSE[$N$ is odd]
\STATE $y \leftarrow y \times X$
\STATE $N \leftarrow N - 1$
\ENDIF
\ENDWHILE
\end{algorithmic}
\end{varwidth}