Beamer theorem numbering issue

Question

I have a beamer presentation containing slides for multiple lectures in a single file. Exercises in the slides should be number continuously from the first lecture to the last. So lecture 1 ends with exercise 10, lecture 2 starts with exercise 11 and so on.

When I use \includeonlyframes to make a presentation for a particular lecture it always starts numbering from one again. So, lecture 2 starts again from 1, rather then 11 I would like to see.

It appears that \includeonlyframes doesn't read frames that are not included at all. Is there a way to make it read all frames and output the right ones, but preserve the numbering in the process?

Answer 1

It appears that \includeonlyframes isn't designed to read all the frames. From the Beamer User Guide, Section 4.3.3 (Ways of Improving Compilation Speed):

This command behaves a little bit like the \includeonly command: Only the frames mentioned in the list are included.

(emphasis mine). Only the section and subsection commands are still executed, for getting correct navigation bars. Since \includeonlyframes is a way to improve the compilation speed, it shouldn't read the contents of the frames. Of course it would be nice to have a version that does it nonetheless ...

I see only one simple way out of your problem: add something like \setcounter{exercise}{10} before your frames for lecture 2, where 10 should be the last exercise from lecture 1. Here's an example:

\documentclass{beamer}
\setbeamertemplate{theorems}[numbered]
\includeonlyframes{t2}
\begin{document}
\begin{frame}[label=t1]
\begin{theorem}
First theorem
\end{theorem}
\end{frame}
\setcounter{theorem}{1}
\begin{frame}[label=t2]
\begin{theorem}
Second theorem
\end{theorem}
\end{frame}
\end{document}

By the way, it would be good if you include an MWE in your next question; it took me some time to write the above code since I didn't know about \setbeamertemplate{theorems}[numbered] before.