mathtools
The following MWE worked in December 2015 based on the archived PDF. But, it does not work today. Any idea?
\documentclass{article}
\usepackage{mathtools}
\DeclarePairedDelimiter{\eceil}{\left\lceil}{\right\rceil}
\begin{document}
$\eceil{\cdot}$
\end{document}
Now with all the options provided by \DeclarePairedDelimiter! See the new definition (without using xparse):
\DeclarePairedDelimiter{\norm}{\lVert}{\rVert}
\makeatletter
\newcommand{\@supnormstar}[1]{\norm*{#1}_\infty}
\newcommand{\@supnormnostar}[2][]{\norm[#1]{#2}_\infty}
\newcommand{\supnorm}{\@ifstar\@supnormstar\@supnormnostar}
\makeatother
For example, the following code:
\[\supnorm{\frac{\sqrt5-1}{2}}^2\]
\[\supnorm*{\frac{\sqrt5-1}{2}}^2\]
\[\supnorm[\big]{\frac{\sqrt5-1}{2}}^2\]
will give you:
You can obtain it with \vvvert from mathabx. Here is a code to use it without loading the mathabx package:
Note: You also have the \vVert and \rVvert delimiters in fdsymbol. Another possibility, if you happen to use fourier, is that it provides a \VERT command for the same delimiter.
\documentclass{article}
\usepackage{mathtools}
\usepackage{etoolbox}
\DeclareFontFamily{U}{matha}{\hyphenchar\font45}
\DeclareFontShape{U}{matha}{m}{n}{
<-6> matha5 <6-7> matha6 <7-8> matha7
<8-9> matha8 <9-10> matha9
<10-12> matha10 <12-> matha12
}{}
\DeclareSymbolFont{matha}{U}{matha}{m}{n}
\DeclareFontFamily{U}{mathx}{\hyphenchar\font45}
\DeclareFontShape{U}{mathx}{m}{n}{
<-6> mathx5 <6-7> mathx6 <7-8> mathx7
<8-9> mathx8 <9-10> mathx9
<10-12> mathx10 <12-> mathx12
}{}
\DeclareSymbolFont{mathx}{U}{mathx}{m}{n}
\DeclareMathDelimiter{\vvvert} {0}{matha}{"7E}{mathx}{"17}%
\DeclarePairedDelimiterX{\normiii}[1]
{\vvvert}
{\vvvert}
{\ifblank{#1}{\:\cdot\:}{#1}}
\begin{document}
\[ \normiii[\Big]{x^k } \qquad \normiii{} \]
\[ \normiii*{\sum_{k \geq 0}^\infty a_k} \]
\end{document}
Best Answer
You should not use
leftandrightin theDeclarePairedDelimiterdefinition. Those are automatically used when you use the command defined there.You would use the starred version for autoscaling, i.e.
\leftand\rightlikeSo
Should work fine and produce