# Delimiter size \big not working with fourier, mathtools packages and 11pt option

I have a document using the fourier font package and mathtools. In mathmode the \big delimiters are the same size as normal sized.

After some debugging I noticed that if I remove the 11pt document option, then this delimiter size does work correctly. This seems to be a bug to me, but my TeX knowledge is too limited to trace it further. Any pointers as to whether this is a bug (and in which package) would be appreciated.

A MWE below. If I remove the 11pt option the norm delimiters are scaled correctly to increasing sizes. Other delimiters such as parentheses scale correctly under both circumstances.

\documentclass[11pt]{article}

\usepackage{mathtools}
\usepackage{fourier}

\begin{document}

$$\|\,\big\|\,\Big\|$$

\end{document}

-

amsmath changes the way LaTeX builds \big delimiters based on the dimensions of a parenthesis. Unfortunately the parenthesis is not as high as amsmath expects. I found a correction that seems to work:

\usepackage{amsmath}
\usepackage{fourier}

\makeatletter
\def\resetMathstrut@{%
\setbox\z@\hbox{%
\mathchardef\@tempa\mathcode\(\relax
\def\@tempb##1"##2##3{\the\textfont"##3\char"}%
\expandafter\@tempb\meaning\@tempa \relax
}%
\ht\Mathstrutbox@1.2\ht\z@ \dp\Mathstrutbox@1.2\dp\z@
}
\makeatother


(notice that mathtools is not involved in this, but it's the called amsmath package the important one.

Complete example:

\documentclass[11pt]{article}
\usepackage{amsmath}
\usepackage{fourier}

\makeatletter
\def\resetMathstrut@{%
\setbox\z@\hbox{%
\mathchardef\@tempa\mathcode\(\relax
\def\@tempb##1"##2##3{\the\textfont"##3\char"}%
\expandafter\@tempb\meaning\@tempa \relax
}%
\ht\Mathstrutbox@1.2\ht\z@ \dp\Mathstrutbox@1.2\dp\z@
}
\makeatother

\begin{document}
$\|\,\big\|\,\Big\|\,\bigg\|\,\Bigg\|$
\end{document}


-
Thanks, indeed this also works. Are there any possible side effects I should be aware of, and is this solution better than what I found? – eldering Jun 24 '12 at 12:53
It may not work with other growing delimiters; I tried with (, [ and \lbrace, the results seem good. – egreg Jun 24 '12 at 13:02

Ok, I've found at least a way to solve it; I added

\DeclareMathSizes{10.95}{11.3}{7.7}{5.5}


to my preamble. I'd be glad if anyone could explain why this is necessary, or if there is a better solution.

-
I don't think this is a good solution, as it changes the size of all math fonts. An "a" in math mode will be 3% higher than an "a" in text mode. Moreover, it won't distinguish between \Big and \bigg, for instance. – egreg Jun 24 '12 at 13:05