Easy way to cross-reference many equations

Question

I got a document with many (over 100) equations, in which I think during the work on it I'll have to change, switch, remove them etc. I often want to refer to an equation but due to the work in progress it's not really convenient to \label every equation e.g. with a number and \ref to it. Is there an easier way to do this with some auto labeling and a straight forward refer even if I change order etc.

So best is just to find a logical way to \label all my equations — Timo Molenkamp, Oct 13 '17 at 10:17
Logical, meaning I think, mnemonic. It serves no use (and may actually throw confusion) to say \begin{equation}E=mc^2\label{eq:1}\end{equation}, but rather one should say something like \begin{equation}E=mc^2\label{eq:einstein}\end{equation}. And you don't have to \label all the equations...only the ones you reference. Bottom line is that automatic labeling is meaningless labeling. — Steven B. Segletes, Oct 13 '17 at 10:21
Since you have some responses below that seem to answer your question, please consider marking one of them as ‘Accepted’ by clicking on the tickmark below their vote count (see How do you accept an answer?). This shows which answer helped you most, and it assigns reputation points to the author of the answer (and to you!). It's part of this site's idea to identify good questions and answers through upvotes and acceptance of answers. — samcarter_is_at_topanswers.xyz, Nov 29 '17 at 09:42

score 5 · Answer 1 · answered Oct 13 '17 at 10:42

If you're \labeling the equations numerically in ascending order, you're not using the tool appropriately. The arguments of \label should indicate, in some abbreviated and hopefully recognizable way, what it being cross-referenced. E.g., one might write

\begin{equation} \label{eq:einstein_energy}
E=mc^2
\end{equation}

With this setup, no matter if the equation is ends up being numbered 1, 55, or any other number, you can cross-reference from anywhere in the document by writing

\ref{eq:einstein_energy}

You certainly won't have to change the argument of \label (and \ref) simply because the number assigned to the equation has changed.

If you need to cross-reference ranges of equations, you should look into loading the cleveref package and using its \crefrange macro, as is demonstrated in the following example. Note that the middle three equations aren't even assigned \labels.

For more information on cross-referencing mechanisms and packages, please the posting Cross-reference packages: which to use, which conflict?

\documentclass{article}
\usepackage[noabbrev]{cleveref} % for "\crefrange" macro
\setlength\textwidth{3in} % just for this example
\begin{document}
\begin{equation}\label{eq:one_one}  1+1=2 \end{equation}
\begin{equation}                    2+2=4 \end{equation}
\begin{equation}                    3+3=6 \end{equation}
\begin{equation}                    4+4=8 \end{equation}
\begin{equation}\label{eq:zero_zero}0+0=0 \end{equation}
A cross-reference to \crefrange{eq:one_one}{eq:zero_zero}.
\end{document}

Easy way to cross-reference many equations

1 Answers1