# Dotted vertical line in math array + siunitx?

This works until I uncomment siunitx. I presume this is a bug? Should I file anywhere?

\documentclass{article}

\usepackage{amsmath}
\usepackage{arydshln}
\usepackage{mathtools}

% Uncommenting this line breaks this document. It will trigger a compilation error on the dotted line indicator.
%\usepackage{siunitx}

\begin{document}

$\begin{array}{c : c : c} 1 & 2 & 3 \\ 4 & 5 & 6 \\ \end{array}$

\end{document}

• Load siunitx before arydshln. And no need to load both mathtools and amsmath. mathtools loads amsmath too. – user11232 Aug 8 '14 at 2:10
• That worked. How did you know? Is there a simple explanation? That seems very sloppy/hacky to me. – clay Aug 8 '14 at 2:41

The siunitx package loads array, part of the standard tools bundle for LaTeX (this is needed to allow the S and s column types to work). However, both array and arydshln make changes to the standard tabular mechanism and I suspect do no tests for other redefinitions. Thus you need to load array before arydshln:

\documentclass{article}

\usepackage{array}
\usepackage{arydshln}
\usepackage{siunitx}

\begin{document}

$\begin{array}{c : c : c : S} 1 & 2 & 3 & 12.3\\ 4 & 5 & 6 & 4.56\\ \end{array}$

\end{document}


(S` column added to show that things still work properly.)