1

Code:

\documentclass{article}
\usepackage[utf8]{inputenc}
\usepackage{amsmath}
\begin{document}
    \begin{align*}
        J
        &= J_0 + 2 m r^2 
        & \label{eq:asdf}\refstepcounter{equation}(\theequation) 
        && \tilde{J} 
        &= J_0 + 2 m \tilde{r}^2 & \refstepcounter{equation}(\theequation)
    \end{align*}
    \eqref{eq:asdf}
\end{document}

Output: outputOfCode

I want to reference (1).

  • 2
    You need to put \label after \refstepcounter (although using align* and then using \refstepcounter by hand is pretty odd:-) – David Carlisle Oct 3 '14 at 14:51
  • 1
    Try running it twice. The first run writes the aux file, the second reads it. – John Kormylo Oct 3 '14 at 14:53
  • May be of interest: http://tex.stackexchange.com/a/42728/2417 – Ian Thompson Oct 3 '14 at 14:58
  • @DavidCarlisle: equation counter is set to 0 before I call \label. That means that there has to appear a (0). If that were true, I would be happy. – Michael Banucu Oct 3 '14 at 14:58
  • 1
    \refstepcounter sets the current label (which is why you need to do that first, as for undoing amsmath definition John beat me by a few seconds:-) – David Carlisle Oct 3 '14 at 15:32
4

Amsmath sets \let\label=\@gobble in align*.

\documentclass{article}
\usepackage[utf8]{inputenc}
\usepackage{amsmath}
\begin{document}
\let\goodlabel=\label
    \begin{align*}
        J
        &= J_0 + 2 m r^2 
        & \refstepcounter{equation}\goodlabel{eq:asdf}(\theequation)
        && \tilde{J} 
        &= J_0 + 2 m \tilde{r}^2 & \refstepcounter{equation}(\theequation)
    \end{align*}
    \eqref{eq:asdf}
\end{document}

gobble

  • Ohh you beat me by 10 sec:-) – David Carlisle Oct 3 '14 at 15:31
  • @David Carlisle - If it makes you feel any better, it took longer than that to crop the image. – John Kormylo Oct 3 '14 at 15:36
  • @JohnKormylo: what is \@gobble? – Michael Banucu Oct 3 '14 at 15:45
  • @Michael Banucu - I've seen it before but never seen the \def. I've always assumed from context that it eats arguments, but otherwise does nothing (like \relax). – John Kormylo Oct 4 '14 at 4:00

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