[Tex/LaTex] Boxed algorithm with caption at top

algorithmscaptionsframedpositioning

I wish to obtain a boxed algorithm with the caption at the top. I also need to control the caption format, and the heading.

I tried using the algorithm package:

%algorithms
\usepackage[boxed]{algorithm}
\usepackage{algorithmicx,algpseudocode}

% Change float style of algorithm from "ruled" to "plaintop"
\floatstyle{plaintop}
\restylefloat{algorithm}

% Change caption format
\captionsetup[algorithm]{font=scriptsize,labelformat=bf-gara,justification=raggedright,singlelinecheck=false,name=Algorithm}

% Change caption heading
\renewcommand{\thealgorithm}{A.\arabic{algorithm}}

which however does not draw the box around the algorithm. I could require all floats to be boxed, but this would affect figures and tables too, which I do not want to be boxed.

Alternatively, I could use the algorithm2e package , which offers more control over caption position, but then I get into troubles when I need to specify caption format and heading:

\thealgorithm undefined. \renewcommand{\thealgorithm}
Argument of \ALG@cmd@2@algorithmiccomment has an extra }. \While{$r\not=0$}\Comment{

How can I save both ways? Thanks!

Best Answer

Write yourself a new style based on the old boxed style:

\documentclass{article}

\usepackage{algorithm,algpseudocode,caption}

% Define a new boxedtopcap float style
\makeatletter
\newcommand\fs@boxedtopcap{\def\@fs@cfont{\bfseries}\let\@fs@capt\floatc@plain
  \def\@fs@pre{\setbox\@currbox\vbox{\hbadness10000
    \moveleft3.4pt\vbox{\advance\hsize by6.8pt
      \hrule \hbox to\hsize{\vrule\kern3pt
        \vbox{\kern3pt\box\@currbox\kern3pt}\kern3pt\vrule}\hrule}}}%
  \def\@fs@mid{\kern2pt}%
  \def\@fs@post{}\let\@fs@iftopcapt\iftrue}
\makeatother

% Change float style of algorithm from "ruled" to "plaintop"
\floatstyle{boxedtopcap}
\restylefloat{algorithm}

% Change caption format
\captionsetup[algorithm]{
  justification = raggedright,
  singlelinecheck = false,
  name = Algorithm
}

% Change caption heading
\renewcommand{\thealgorithm}{A.\arabic{algorithm}}

\begin{document}

\begin{algorithm}
  \caption{Euclid's algorithm}
  \begin{algorithmic}[1]
    \Procedure{Euclid}{$a,b$}\Comment{The g.c.d.\ of $a$ and $b$}
      \State $r \gets a \bmod b$
      \While{$r \neq 0$}\Comment{We have the answer if $r$ is $0$}
        \State $a \gets b$
        \State $b \gets r$
        \State $r \gets a \bmod b$
      \EndWhile
      \State \textbf{return} $b$\Comment{The g.c.d.\ is $b$}
    \EndProcedure
  \end{algorithmic}
\end{algorithm}

\end{document}

Related Solutions

[Tex/LaTex] Adjust spacing of algorithm float caption

First of all many of us (if not even most of us) don't have LyX so better offer a LaTeX code instead. Second, better give a minimal example code, because usually reducing the code to it's minimum is the very first step when analyzing a LaTeX problem.

An reasonable example code showing the problem would be something like this:

\documentclass{scrbook}
\usepackage{float}
\usepackage{caption}
\usepackage[dvipsnames,svgnames,x11names,table]{xcolor}

\usepackage{algorithm}

% Use a hyphen for captions, and make links give a bit of space.
\DeclareCaptionFormat{algorithm}{\vspace{-1ex}\colorbox[HTML]{A6BFF2}{%
  \parbox[c][1.75em][c]{\textwidth}{\hspace{0.25em}#1#2#3}}}
\captionsetup[algorithm]{format=algorithm}

\begin{document}
\begin{algorithm}
\caption{Blah\ldots}
A
\end{algorithm}
\end{document}

But now let's take a look at your problem: The extra spaces are typeset by the "ruled" float style offered by the float package. One can change this by defining an own float style and making the algorithm environment using this one instead of the original one. I did that by copying the "ruled" style and modifying it:

% Define own float style called "algorithm"
\makeatletter
\newcommand\fs@algorithm{%
  \let\@fs@capt\floatc@algorithm
  \def\@fs@pre{\hrule height.8pt depth0pt\relax}% \kern2pt removed
  \def\@fs@mid{\hrule\kern2pt}%  \kern2pt removed
  \def\@fs@post{\kern2pt\hrule\relax}%
  \let\@fs@iftopcapt\iftrue}
\makeatother

% Make the algorithm environment use the algorithm float style
\floatstyle{algorithm}
\restylefloat{algorithm}

So in total we have: (Please note that I have removed the extra \vspace of yours.)

\documentclass{scrbook}
\usepackage{float}
\usepackage{caption}
\usepackage[dvipsnames,svgnames,x11names,table]{xcolor}

\usepackage{algorithm}

% Define own float style called "algorithm"
\makeatletter
\newcommand\fs@algorithm{%
  \let\@fs@capt\floatc@algorithm
  \def\@fs@pre{\hrule height.8pt depth0pt\relax}% \kern2pt removed
  \def\@fs@mid{\hrule\kern2pt}%  \kern2pt removed
  \def\@fs@post{\kern2pt\hrule\relax}%
  \let\@fs@iftopcapt\iftrue}
\makeatother

% Make the algorithm environment use the algorithm float style
\floatstyle{algorithm}
\restylefloat{algorithm}

% Use a hyphen for captions, and make links give a bit of space.
\DeclareCaptionFormat{algorithm}{\colorbox[HTML]{A6BFF2}{%
  \parbox[c][1.75em][c]{\textwidth}{\hspace{0.25em}#1#2#3}}}
\captionsetup[algorithm]{format=algorithm}

\begin{document}
\begin{algorithm}
\caption{Blah\ldots}
A
\end{algorithm}
\end{document}

Please note that this code still contains 2x \kern2pt, one before and one after the algorithm body. If you don't like this extra vertical space, too, just remove them.

[Tex/LaTex] placing caption on the top right or top left –

As Harish Kumar mentioned in his comment. you can use \sidecaptionvpos to control the vertical placement of the caption and the innercaption package option to place the captions right on left pages and left on right pages (as your example seems to show). In the following example I also used \subcaptionbox from the subcaption package to place the subfigures; the demo option for graphicx simply replaces the images with black rectangles (do notuse that option in your actual code):

\documentclass{article}
\usepackage[demo]{graphicx}
\usepackage{caption}
\usepackage{subcaption}
\usepackage[innercaption]{sidecap}
\usepackage{lipsum}

\sidecaptionvpos{figure}{t}
\begin{document}

\begin{SCfigure}
  \centering
  \begin{minipage}{5.5cm}
  \subcaptionbox{A subfigure\label{fig:sub1}}{\includegraphics{name1}}\\
  \subcaptionbox{Another subfigure\label{fig:sub2}}{\includegraphics{name2}}
  \end{minipage}
  \caption{\protect\lipsum[2]}
\end{SCfigure}

\end{document}

enter image description here

Best Answer

Related Solutions

[Tex/LaTex] Adjust spacing of algorithm float caption

[Tex/LaTex] placing caption on the top right or top left –

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