# subcaption: caption' package not loaded

I am trying to use subfig in ACM class file, but it issues an error that 'caption' package not loaded. I downloaded the 1.3 version of caption (as suggested by ACM), but still the same. Here is the code

\documentclass{sig-alternate}
\usepackage{graphicx, booktabs, multicol,multirow,bigstrut,rotating}
\usepackage{caption}
\usepackage{subcaption}
\begin{document}
\begin{figure}[t]
\centering
\begin{subfigure}[b]{0.3\textwidth}
\includegraphics[scale=0.12]{figures/fig3} \caption{Comparison} \label{Fig:Speed}
\end{subfigure}
\begin{subfigure}[b]{0.3\textwidth}
\includegraphics[scale=0.12]{figures/fig3} \caption{Comparison} \label{Fig:Time}
\end{subfigure}%
\end{figure}
\end{document}


when compiling there are couple of errors including:

1. subcaption: caption' package not loaded
2. Environment subfigure undefined. \begin{subfigure}
3. Missing number, treated as zero \begin{subfigure}[b]{0.3\textwidth}

Any hint is appreciated.

• The package caption (and so also subcaption) is not compatible with the sig-alternate class. – egreg Jan 31 '14 at 11:55
• Oh, thanks. Any other option? Subbottom also does not work – Espanta Jan 31 '14 at 12:01
• Maybe helpful: tex.stackexchange.com/a/129594/41085 – Crissov Jan 31 '14 at 12:18
• The suggestion of @Crissov solves the problem, by restoring the (ugly) boldface captions that ACM requires, so why is the below answer accepted ? (it is correct, but leads people to not use the subcaption package, which is newer and maintained). – Ioannis Filippidis Jun 22 '14 at 1:54

Since sig-alternate defines its own \caption command, the caption package is not really compatible with it; subcaption might work, but the result is not guaranteed. You can do with subfig:

\PassOptionsToPackage{demo}{graphicx} % just for the example
\documentclass{sig-alternate}

\usepackage[caption=false]{subfig}
\usepackage{lipsum} % just for the example

\begin{document}

\lipsum[1-2]

\begin{figure}[ht]
\centering

\subfloat[Comparison one]{%
\includegraphics[width=0.3\textwidth]{figures/fig3}%
\label{Fig:Speed}%
}

\subfloat[Comparison two]{%
\includegraphics[width=0.3\textwidth]{figures/fig3}%
\label{Fig:Time}%
}
\end{figure}

\lipsum
\end{document}


The two lines marked just for the example are for producing the image, don't use them yourself.

Don't use scale=, but prefer setting the width. You should probably use multiples of \columnwidth rather than \textwidth, as the class produces two column documents.

• great. it works perfect. – Espanta Feb 2 '14 at 15:23