[Tex/LaTex] Caption numbering breaking up an algorithm with algorithmicx

Question

According to its documentation, algorithmicx package allows break up an algorithm inside a document, as follows:

Related tex code is:

\documentclass{article}
\usepackage{algorithm}
\usepackage{algpseudocode}
\begin{document}
\begin{algorithm}
\caption{Part 1}
\begin{algorithmic}[1]
\Procedure {BellmanKalaba}{$G$, $u$, $l$, $p$}
\ForAll {$v \in V(G)$}
\State $l(v) \leftarrow \infty$
\EndFor
\State $l(u) \leftarrow 0$
\Repeat
\For {$i \leftarrow 1, n$}
\State $min \leftarrow l(v_i)$
\For {$j \leftarrow 1, n$}
\If {$min > e(v_i, v_j) + l(v_j)$}
\State $min \leftarrow e(v_i, v_j) + l(v_j)$
\State \Comment For some reason we need to break here!
\algstore{bkbreak}
\end{algorithmic}
\end{algorithm}
And we need to put some additional text between\dots
\begin{algorithm}[h]
\caption{Part 2}
\begin{algorithmic}[1]
\algrestore{bkbreak}
\State $p(i) \leftarrow v_j$
\EndIf
\EndFor
\State $l’(i) \leftarrow min$
\EndFor
\State $changed \leftarrow l \not= l’$
\State $l \leftarrow l’$
\Until{$\neg changed$}
\EndProcedure
\end{algorithmic}
\end{algorithm}
\end{document}

It's easy to note that the caption number is incremented between the two pieces of code (Algorithm 3 for the first, Algorithm 4 for the second). Moreover, is it possible to have the same number for both? If yes, how can I do that?

Answer 1

As egreg has mentioned in a comment, one option would be to use

\addtocounter{algorithm}{-1} 

before \caption{Part 2}. Another option, not requiring manually changing counters and that additionally gives you the possibility to use a customized formatting for the continued algorithm, would be to use \ContinuedFloat from the caption package. An example with the default caption format for \ContinuedFloat:

\documentclass{article}
\usepackage{caption}
\usepackage{algorithm}
\usepackage{algpseudocode}
\begin{document}
\begin{algorithm}
\caption{Part 1}
\begin{algorithmic}[1]
\Procedure {BellmanKalaba}{$G$, $u$, $l$, $p$}
\ForAll {$v \in V(G)$}
\State $l(v) \leftarrow \infty$
\EndFor
\State $l(u) \leftarrow 0$
\Repeat
\For {$i \leftarrow 1, n$}
\State $min \leftarrow l(v_i)$
\For {$j \leftarrow 1, n$}
\If {$min > e(v_i, v_j) + l(v_j)$}
\State $min \leftarrow e(v_i, v_j) + l(v_j)$
\State \Comment For some reason we need to break here!
\algstore{bkbreak}
\end{algorithmic}
\end{algorithm}
And we need to put some additional text between\dots
\begin{algorithm}[h]
\ContinuedFloat
\caption{Part 2}
\begin{algorithmic}[1]
\algrestore{bkbreak}
\State $p(i) \leftarrow v_j$
\EndIf
\EndFor
\State $l’(i) \leftarrow min$
\EndFor
\State $changed \leftarrow l \not= l’$
\State $l \leftarrow l’$
\Until{$\neg changed$}
\EndProcedure
\end{algorithmic}
\end{algorithm}
\end{document}

An an example with a modified format for the caption of continued floats:

\documentclass{article}
\usepackage{caption}
\usepackage{algorithm}
\usepackage{algpseudocode}

\makeatletter
\DeclareCaptionLabelFormat{algcontinued}{\ALG@name~#2 (Continued)}
\makeatother
\captionsetup[ContinuedFloat]{labelformat=algcontinued}

\begin{document}
\begin{algorithm}
\caption{Part 1}
\begin{algorithmic}[1]
\Procedure {BellmanKalaba}{$G$, $u$, $l$, $p$}
\ForAll {$v \in V(G)$}
\State $l(v) \leftarrow \infty$
\EndFor
\State $l(u) \leftarrow 0$
\Repeat
\For {$i \leftarrow 1, n$}
\State $min \leftarrow l(v_i)$
\For {$j \leftarrow 1, n$}
\If {$min > e(v_i, v_j) + l(v_j)$}
\State $min \leftarrow e(v_i, v_j) + l(v_j)$
\State \Comment For some reason we need to break here!
\algstore{bkbreak}
\end{algorithmic}
\end{algorithm}
And we need to put some additional text between\dots
\begin{algorithm}[h]
\ContinuedFloat
\caption{Part 2}
\begin{algorithmic}[1]
\algrestore{bkbreak}
\State $p(i) \leftarrow v_j$
\EndIf
\EndFor
\State $l’(i) \leftarrow min$
\EndFor
\State $changed \leftarrow l \not= l’$
\State $l \leftarrow l’$
\Until{$\neg changed$}
\EndProcedure
\end{algorithmic}
\end{algorithm}
\end{document}