Placing a single algorithm in two columns

Question

I have a single-column document and to save space I would like to make a long algorithm (produced using packages algorithm and algorithmic) to be double-column. That is, I would like the float content to start on the left column and continue on the right column, where the rest of the document is single column. I can place two algorithms side by side within a figure environment, but I am not sure if partitioning a single algorithm into columns can be done.

Answer 1

The multicol package to the rescue!

\documentclass{article}

\usepackage{lipsum}
\usepackage{algorithm,algorithmic}
\usepackage{multicol}

\begin{document}
\lipsum[1]
\begin{algorithm}
\caption{Calculate $y = x^n$}
\label{alg1}
\begin{multicols}{2}
\begin{algorithmic}[1]
  \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{multicols}
\end{algorithm}
\lipsum[2]
\end{document}