# Specific unit output using siunitx

Consider the following example.

I would like to use the \SI command from siunitx to type the following:

\documentclass{article}

\usepackage[separate-uncertainty=true]{siunitx}

\begin{document}

\noindent What I have:
$\SI{6.67384(80)e-11}{\N\square\m\per\square\kg}$
What I would like:
$\num{6.67384(80)e-11}\,\si{\N\square} \cdot (\si{\m/\kg})^{2}$

\end{document}


• The current situatuion is that you can'd do this directly using the tools in the package. May 21 '13 at 14:32
• Is the desired output consistent with SI's specifications? May 21 '13 at 14:33
• @egreg I'm not sure. :( I just made the assumption that it is possible with siunitx, considering the versatility of the package. May 21 '13 at 14:39
• @SvendTveskæg With respect to consistency, please have a look at "SI Unit rules and style conventions", available at physics.nist.gov/cuu/Units/checklist.html.
– user13907
May 21 '13 at 16:03
• @Papiro Good point. Even though it seems it be against the rules and conventions, I would like to have it as explained. Can it be done with \SI? May 21 '13 at 16:07

## 1 Answer

I think, Joseph is wrong. You can do this very easily with siunitx, although it seems a bit unaesthetical:

\documentclass{article}
\usepackage[separate-uncertainty=true,inter-unit-product=\ensuremath{{}\cdot{}}]{siunitx}
\DeclareSIUnit{\myunit}{(m/kg)}
\begin{document}
$\SI{6.67384(80)e-11}{\N\myunit\squared}$
\end{document}

• I meant that you can't auto-format from \N\square\m\per\square\kg. May 21 '13 at 16:27
• Even if there were some functionality involved, no software could completely auto-format out of this given input, because markup is missing. How should the software know, which units should be inside the brackets and which not? May 21 '13 at 19:26
• The question doesn't make it explicit, but I was working on the assumption that the brackets were meant to cover 'units raised to the same power'. May 21 '13 at 21:13
• @JosephWright It is indeed meant to cover units raised to the same power. May 21 '13 at 22:08
• @SvendTveskæg: What reason is there behind grouping units with the same power? It seems to me, that in general it's more important to have compound units with special meanings like m/s^2 or eV. Creating them is possible with SIunitx. In this example, there is only one caveat: What if you want that compound unit m/kg singularly and therefore without parentheses? May 22 '13 at 6:33