How to write an Equation with the Units aligned off right and adapted Bracket Heights around the Unit?

Question

Assumed I have this MWE to align the units off right:

\documentclass{article}
\usepackage{amsmath}
\usepackage{siunitx}

\makeatletter
\providecommand\add@text{}
\newcommand\tagaddtext[1]{%
  \gdef\add@text{#1\gdef\add@text{}}}% 
\renewcommand\tagform@[1]{%
  \maketag@@@{\llap{\add@text\qquad}(\ignorespaces#1\unskip\@@italiccorr)}%
}
\makeatother

\begin{document}

Unfortunately the bracket does not fit to the height of the unit.
The units exponent is already positioned above the upper edge of the bracket. :-(

\begin{equation}
    A = B + C       \tagaddtext{[\si{\square\meter}]}
\end{equation}

How can I change this behavior?



\end{document}

Screenshot of the result:

Description of the eyesore:

As you can see the corresponding brackets do not automatically adapt to the height of the unit. The exponent is higher than the bracket.

How can I change that behavior, so that the brackets will automatically adjust to the height of the highest/lowest point of the unit?

You can use \tagaddtext{$\left[\si{\square\meter}\right]$}. But this is usually not recommended. The image you show is the correct behavior AFAIK. — Peter Grill, Dec 06 '18 at 19:44
@PeterGrill: Thanks a lot! Could I implement the brackets into the \newcommand-configuration already? So that I only have to write \tagaddtext{\si{\square\meter}} into the document text and the brackets will show up automatically? — Dave, Dec 06 '18 at 19:47
@PeterGrill: Excuse me, one more question: Why is your approach usually not recommended? Is it faulty typography to increase the brackets size matching to the exponents? — Dave, Dec 06 '18 at 21:57
The issues with \left...\right are discussed in Is it ever bad to use \left and \right?, “(” or “\left(” parentheses?, What is the correct way to do delimiters? and [Difference between \big[ and \biglhttps://tex.stackexchange.com/q/1232/4301. — Peter Grill, Dec 07 '18 at 00:21
@PeterGrill: Ah, I understand! Thank you very much for your help! I will stop using \left[ ... \right] now at all. I never tought about those spacing problems... — Dave, Dec 07 '18 at 08:27

score 2 · Accepted Answer · answered Dec 06 '18 at 19:59

2

I propose for what it's worth a work-around with flalign and an \addunit command:

\documentclass{article}
\usepackage{showframe}
\renewcommand{\ShowFrameLinethickness}{0.3pt}
\usepackage{mathtools}
\usepackage{siunitx}

\newcommand{\addunit}[1]{\mathllap{\left[\si{#1}\right]\quad}}

\begin{document}

\begin{flalign}
 & & A & = B + C & & \addunit{\square\meter}
\end{flalign}

\end{document}

answered Dec 06 '18 at 19:59

Bernard

271,350

Thanks a lot! So I should stop using \begin{equation}blabla\end{equation}? Or better use \begin{flalign} inside of \begin{equation}? – Dave Dec 06 '18 at 21:46
If you want to use \addunit, yes, use flalign in the place of equation – flalign can't be used inside another math environment, and flaligned does not exist. – Bernard Dec 06 '18 at 21:51

How to write an Equation with the Units aligned off right and adapted Bracket Heights around the Unit?

1 Answers1