How to reference an equation number within TikZ

Question

I'm attempting to dynamically reference an Equation number in tikzpicture (via \eqref or \ref) using the following:

% Filename:  Test.tex (say)
\documentclass{article}
\usepackage{latexsym,amsfonts,amsthm,amssymb,amsmath}
\usepackage{tikz}
\usepackage{pgfplots}
\pgfplotsset{compat=newest}

% Due to a large number of Tikz plots
\usepgfplotslibrary{external}
\tikzexternalize

\begin{document}
Here is an equation:
\begin{equation}
    \label{eqOne}
    y = x^2
\end{equation}
that I'd like to appear in TikZ.

\begin{figure}[htbp]
\centering
\begin{tikzpicture}
\begin{axis}[%
xmajorgrids,
ymajorgrids
]

\addplot[const plot,color=red,solid,line width=0.5pt] plot table[row sep=crcr] {%
0  0\\
1  1\\
2  4\\
3  9\\
};
]
\node[right, align=left, inner sep=0mm] at (axis cs:2,4) {Equation \eqref{eqOne}};
\end{axis}
\end{tikzpicture}
\end{figure}

\end{document}

but this won't work via pdflatex -shell-escape Test.tex. The output generated shows 'Equation (??)'

By trial and error, dynamic referencing seems to only work without \usepgfplotslibrary{external} and \tikzexternalize, but I need these two lines due to the number of TikZ plots that I have.

Is there a way around this dynamic referencing problem; perhaps I'm going about this the wrong way?

Many thanks!

Please minimize your code as much as possible and describe your compilation routine. As Peter mentioned, pdfLaTeX has to be invoked twice. Thank you. — LaRiFaRi, Jun 08 '15 at 22:52
@LaRiFaRi: Looks like this is more than the usual "just run it twice" issue. Does References in externalized pgfplots answer your question. If so, we'll close this question as a duplicate. — Peter Grill, Jun 09 '15 at 00:04
Alternatively, you could use \theequation until the next equation, or use \global\edef\eqOne{\theequation} to store the number. — John Kormylo, Jun 09 '15 at 14:23
Many thanks for everyone's great feedback and help! Peter's link to references in externalized pgfplots solved this problem! — Michael, Jun 09 '15 at 21:17

score 0 · Answer 1 · edited Apr 13 '17 at 12:35

Peter's link to references in externalized pgfplots solved my problem!

Just to be explicit for others: for this example (using file Test.tex), the figure # in question (starting from 0) is 0 (here, there's only one figure); so:

pdflatex -shell-escape -interaction=batchmode -jobname "Test-figure0" "\def\tikzexternalrealjob{Test}\input{Test}"

followed by

pdflatex -shell-escape Test.tex

worked!

My sincere thanks to Peter and this forum/group!!

How to reference an equation number within TikZ

1 Answers1