Revtex4-1 and algorithm2e indentation clash

Question

there seems to exists a clash between revtex4-1 and the algorithm2e package. Whenever I try to insert an algorithm block when using the revtex4-1 document class, the tabulation is not working properly. The following latex code should hopefully be self explanatory.

%\documentclass[10]{article}
\documentclass[10]{revtex4-1}

% these are to avoid another clash between revtex and algorithm2e
\makeatletter
\newif\if@restonecol
\makeatother
\let\algorithm\relax
\let\endalgorithm\relax
% needed includes
\usepackage[ruled]{algorithm2e}
\usepackage{algorithmic}

\begin{document}

The following pseudocode exibits a clash between revtex4-1 and algorithm2e.

\begin{algorithm}
\caption{Calculate something}
\begin{algorithmic}
\FOR{every thing you}
    \FOR{every step you}
        \STATE{compute something}
    \ENDFOR
\ENDFOR
\end{algorithmic}
\end{algorithm}

\end{document}

This is a how the rendered pdf shows on my system (sorry, I'm not allowed to insert images in this post). The tabulation is correct when using the simple article document class. I am using Texmaker (with texLive) under Ubuntu 10.04.

Using the revtex4-1 document class:

for every thing you do
for every step you do
compute something
end for
end for

Using the article document class:

for every thing you do
    for every step you do
        compute something
    end for
end for

Anybody with a solution to make these two work together?

Answer 1

There is an incompatibility between the algorithm2e/algorithmic packages and revtex4-1; one possibility is to use algcompatible instead of algorithmic (the syntax of the commands is the same and this solves the indentation problem) and to use the newfloat package to define a new algorithm float. Here's an example illustrating this approach (I used a table and a figure environments to show how the newly defined float behaves consistently with the class):

\documentclass{revtex4-1}
\usepackage{algcompatible}
\usepackage{newfloat}

\DeclareFloatingEnvironment[
    fileext=loa,
    listname=List of Algorithms,
    name=ALGORITHM,
    placement=tbhp,
]{algorithm}

\begin{document}

\begin{figure}
\rule{2cm}{2cm}
\caption{A test caption for a figure}
\end{figure}

\begin{table}
\rule{2cm}{2cm}
\caption{A test caption for a table}
\end{table}

\begin{algorithm}
\begin{algorithmic}
\FOR{every thing you}
    \FOR{every step you}
        \STATE{compute something}
    \ENDFOR
\ENDFOR
\end{algorithmic}
\caption{Calculate something}
\end{algorithm}

\end{document}

If one wants to keep the ruled style of the algorithm environmet, as defined in algorithm2e, some additional work has to be done; in this case, the caption package could be used (providing one makes the necessary adjustments to recover the formatting defined in revtex4-1); here's such possibility with a little example:

\documentclass{revtex4-1}
\usepackage{newfloat,algcompatible}
\usepackage[size=small]{caption}
\usepackage{etoolbox}

\AtBeginEnvironment{algorithm}{\noindent\hrulefill\par\nobreak\vskip-5pt}
\usepackage{newfloat}

\DeclareFloatingEnvironment[
    fileext=loa,
    listname=List of Algorithms,
    name=ALGORITHM,
    placement=tbhp,
]{algorithm}
\DeclareCaptionFormat{algorithms}{\vskip-15pt\hrulefill\par#1#2#3\vskip-6pt\hrulefill}
\captionsetup[algorithm]{singlelinecheck=off,format=algorithms}

\begin{document}

\begin{figure}
\rule{2cm}{2cm}
\caption{A test caption for a figure}
\end{figure}

\begin{algorithm}
\begin{algorithmic}
\FOR{every thing you}
    \FOR{every step you}
        \STATE{compute something}
    \ENDFOR
\ENDFOR
\end{algorithmic}
\caption{Calculate something}
\end{algorithm}

\end{document}

If, for some reason, the newfloat packageis not available, one can use the trivfloat instead:

\documentclass{revtex4-1}
\usepackage{algcompatible}
\usepackage[floatrow]{trivfloat}

\trivfloat{algorithm}
\renewcommand\algorithmname{ALGORITHM}

\begin{document}

\begin{figure}
\rule{2cm}{2cm}
\caption{A test caption for a figure}
\end{figure}

\begin{table}
\rule{2cm}{2cm}
\caption{A test caption for a table}
\end{table}

\begin{algorithm}
\begin{algorithmic}
\FOR{every thing you}
    \FOR{every step you}
        \STATE{compute something}
    \ENDFOR
\ENDFOR
\end{algorithmic}
\caption{Calculate something}
\end{algorithm}

\end{document}

Answer 2

I had to work out a bit the solution provided by Gonzalo Medina using Revtex4-1 to fix some horizontal line placement when floating the pseudocode and putting the caption at the top of it and also update the very usefull \Comment command (also add an \Input command that might be usefull for some of you).

\documentclass[aps,prl,reprint,groupedaddress,amsmath, amssymb, showpacs]{revtex4-1}

\usepackage{newfloat,algcompatible}
\usepackage[size=small]{caption}
\usepackage{etoolbox}

\AtEndEnvironment{algorithm}{\noindent\hrulefill\par\nobreak\vskip-8pt}

\DeclareFloatingEnvironment[
    fileext=loa,
    listname=List of Algorithms,
    name=ALGORITHM,
    placement=tbhp,
]{algorithm}
\DeclareCaptionFormat{algorithms}{\vskip-15pt\hrulefill\par#1#2#3\vskip-6pt\hrulefill}
\captionsetup[algorithm]{singlelinecheck=off,format=algorithms}

%\renewcommand{\algorithmicrequire}{\textbf{Input:}}
\renewcommand\algorithmiccomment[1]{\hfill\(\triangleright\) #1}%       

\algblock[Input]{Input}{EndInput}
\algblockdefx[Input]{Input}{EndInput}%
    [1]{\textbf{Input} #1}%
    {}

\begin{document}

\begin{algorithm}[t]
\caption {Compute Something}
\begin{algorithmic}
\Input{Something you have}\EndInput
\FOR{Something you know}
\State{Something you can}
\ENDFOR
\end{algorithmic}
\end{algorithm}

\end{document}

If you don't have the newfloat package available in your miktex distributino, you should be able to found it here

http://www.ctan.org/tex-archive/macros/latex/contrib/caption

just download the entire caption package, compile caption.ins using latex and this will create newfloat.sty that you can move to your local directory.

Best