[Tex/LaTex] Create a smart cross-reference to a line in an ‘algorithmic’ environment using \autoref

algorithmicxalgorithmsautorefcross-referencing

To set the name of the \autoref command for an algorithm I use:

\newcommand{\algorithmautorefname}{Algorithm}

like commented here. I would also like to be able to refer to lines within an algorithmic environment with line x.

\begin{algorithm}
\label{alg:myalg}
\begin{algorithmic}[1]
  \State Do X 
  \State Do Y \label{algl:y}
  \State $x = y + z$
\end{algorithmic}
\end{algorithm}

\autoref{alg:myalg} gives me correctly Algorithm 1. In addition, I would also like to have \autoref{algl:y} generate line 2. Until now I'm using: line~\ref{algl:y}.

Seeing the same answer you can define the autoref names by: \....autorefname.
But then he mentions that some counters are hidden, for example the line numbering: \c@ALG@line. Is it possible to create an autoref name for them?

I have tried:

\newcommand{\ALGlineautorefname}{line}
\newcommand{\ALG_lineautorefname}{line}
\newcommand{\ALG@lineautorefname}{line}

but none work and only the first compiles.

If possible, how can I create an \autorefname for a line in an algorithmic environment.

Best Answer

The line counter is hidden from hyperref's \autoref because the counter is stepped using \addtocounter{ALG@line}{1} instead of \refstepcounter{ALG@line}. The following patch corrects this, allowing you to define \ALG@lineautorefname:

\documentclass{article}

\usepackage{algorithm,algpseudocode}
\usepackage{hyperref,etoolbox}

\makeatletter
\patchcmd{\ALG@step}{\addtocounter{ALG@line}{1}}{\refstepcounter{ALG@line}}{}{}
\newcommand{\ALG@lineautorefname}{Line}
\makeatother

\newcommand{\algorithmautorefname}{Algorithm}

\begin{document}  

See \autoref{alg:myalg}, specifically \autoref{algl:y}.

\begin{algorithm}
  \caption{An algorithm}\label{alg:myalg}
  \begin{algorithmic}[1]
    \State Do X 
    \State Do Y \label{algl:y}
    \State $x = y + z$
  \end{algorithmic}
\end{algorithm}

\end{document}

Related Solutions

[Tex/LaTex] Algorithm and IEEEtran

The IEEEtran's documentation suggests:

B. Algorithms

IEEE publications use the figure environment to contain algorithms that are not to be a part of the main text flow. Peter Williams’ and Rogerio Brito’s algorithmic.sty package [24] or Szász János’ algorithmicx.sty package [25] (the latter is designed to be more customizable than the former) may be of help in producing algorithm-like structures (although authors are of course free to use whatever LaTeX commands they are most comfortable with in this regard). However, do not use the floating algorithm environment of algorithm.sty (also by Williams and Brito) or algorithm2e.sty (by Christophe Fiorio) as the only floating structures IEEE uses are figures and tables. Furthermore, IEEEtran will not be in control of the (non-IEEE) caption style produced by the algorithm.sty or algorithm2e.sty float environments.

So, as suggested, do not use the algorithm floating environment; you can wrap your algorithm inside a figure (or figure*) environment (if a caption is required and the captions are to be IEEEtran compliant) and use the algorithmicx package ; something like this:

\documentclass{IEEEtran}
\usepackage{algpseudocode}

\begin{document}

\begin{figure}
\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{Euclid's algorithm}\label{euclid}
\end{figure}

\end{document}

enter image description here

If no caption is required, then simply don't use the figure environment.

[Tex/LaTex] Customizing some aspect of algorithmic environment

To restart line numbering from 1, you have to reset the counter ALG@line, so we define a new command \resetline to be issued when you want that change:

\makeatletter
\newcommand{\resetline}{\setcounter{ALG@line}{0}}
\makeatother

In regards of the spacing between two functions, you can use a normal skip instead of issuing a \Statex (\smallskip, \medskip, \bigskip).

MWE

\documentclass{article}
\usepackage{algorithm}
\usepackage[noend]{algpseudocode}

\makeatletter
\newcommand{\resetline}{\setcounter{ALG@line}{0}}
\makeatother

\begin{document}

\begin{algorithm}[H]
    \caption{Calcola il grado di ogni vertice del grafo $G = (V,E)$}
    \label{degree}
    \begin{algorithmic}[1]
        \Function{\textsc{Map}$( \left \langle u;v \right \rangle )$}{}
            \State \textbf{emit} $\left \langle u;v \right \rangle$
        \EndFunction
        \medskip\resetline
        \Function{\textsc{Reduce}$( \left \langle u;\Gamma(u) \right \rangle )$}{}
            \State $d(u) \gets 0$
            \ForAll{$v \in \Gamma(u)$}
                \State $d(u) \gets d(u) + 1$
            \EndFor
            \State \textbf{emit} $\left \langle u;d(u) \right \rangle$
        \EndFunction
    \end{algorithmic}
\end{algorithm}

\end{document}

Output:

enter image description here

The little gap related to the noend option is to indicate the end of the function, so I'll leave it as is, but if you really want to remove it, you can add these lines in your preamble (require the etoolbox package):

\patchcmd{\ALG@doentity}
  {\item[]\nointerlineskip}
  {\relax}
  {}
  {}

Complete code:

\documentclass{article}
\usepackage{algorithm}
\usepackage[noend]{algpseudocode}
\usepackage{etoolbox}

\makeatletter
\newcommand{\resetline}{\setcounter{ALG@line}{0}}
\patchcmd{\ALG@doentity}
  {\item[]\nointerlineskip}
  {\relax}
  {}
  {}
\makeatother

\begin{document}

\begin{algorithm}[H]
    \caption{Calcola il grado di ogni vertice del grafo $G = (V,E)$}
    \label{degree}
    \begin{algorithmic}[1]
        \Function{\textsc{Map}$( \left \langle u;v \right \rangle )$}{}
            \State \textbf{emit} $\left \langle u;v \right \rangle$
        \EndFunction
        \medskip\resetline
        \Function{\textsc{Reduce}$( \left \langle u;\Gamma(u) \right \rangle )$}{}
            \State $d(u) \gets 0$
            \ForAll{$v \in \Gamma(u)$}
                \State $d(u) \gets d(u) + 1$
            \EndFor
            \State \textbf{emit} $\left \langle u;d(u) \right \rangle$
        \EndFunction
    \end{algorithmic}
\end{algorithm}

\end{document}

Output:

enter image description here

Best Answer

Related Solutions

[Tex/LaTex] Algorithm and IEEEtran

[Tex/LaTex] Customizing some aspect of algorithmic environment

Related Question