# Matrix looks flat

I would like to typeset a partitioned matrix in LaTeX with dashed lines. After a quick search on TeX.SE, I found this post with a nice example of such matrices. I tried it on my computer and the result looks "flat". By "flat", I mean that the matrix doesn't look square.

Here is my example :

\documentclass[a4paper,10pt]{article}
\usepackage{arydshln}
\setlength{\dashlinegap}{2pt}

\begin{document}
$\Gamma = \left(\begin{array}{c:c} \Gamma_{A} & \Gamma_{AB} \\ \hdashline (\Gamma_{AB})^\top & \Gamma_{B} \end{array} \right)$
\end{document}


Here is the result of the previous code :

How can I make the matrix look square ?

You can move the lines further apart by specifying arraystretch:

\documentclass[a4paper,10pt]{article}
\usepackage{arydshln}
\setlength{\dashlinegap}{2pt}

\begin{document}

$\Gamma = \left({\renewcommand*{\arraystretch}{1.5} \begin{array}{c:c} \Gamma_{A} & \Gamma_{AB} \\ \hdashline (\Gamma_{AB})^\top & \Gamma_{B} \end{array}} \right)$

\end{document}


Here I have localised the change to a group containing the array.

An alternative way to tweak this, avoid the delimiters increasing too much is to add inisible vertical rules of appropiate height / depth:

\documentclass[a4paper,10pt]{article}
\usepackage{arydshln}
\setlength{\dashlinegap}{2pt}

\begin{document}

$\Gamma = \left( \begin{array}{c:c} \vrule width 0pt depth 6pt \Gamma_A & \Gamma_{AB} \\ \hdashline \vrule width 0pt height 12pt (\Gamma_{AB})^\top & \Gamma_{B} \end{array} \right)$

\end{document}


but choosing the correct values here is rather more ad hoc.