Is there anything like "displaystyle" for "arrays"? [duplicate]

Question

I have this equation and I would like to "get more space" into it, how to do it?

\documentclass[a4paper,12pt]{article}

\usepackage{amsmath}
\usepackage{amssymb}

\begin{document}

\newcommand{\vnull}{\boldsymbol{0}}
\newcommand{\vK}{\boldsymbol{K}}
\newcommand{\vN}{\boldsymbol{N}}
\newcommand{\vT}{\boldsymbol{T}}
\newcommand{\vD}{\boldsymbol{D}}
\begin{equation*}
  \left(
    \begin{array}{l|l|l}
      \vK & \vN^\top & \vT^\top \\
      \hline
      - \rho \vD(\mathcal{A}_\nu) \vN & \vD(\mathcal{I}_\nu) & \vnull\\
      \hline
      - \rho \vD(\mathcal{A}_t) \vT & \vnull
                     & \vD(\mathcal{I}_t^+ \cup \mathcal{I}_t^-)
    \end{array}
  \right)
\end{equation*}

\end{document} 

Answer 1

Define a \bigstrut and add it to each line. I realize one can also do something like \renewcommand\arraystretch{3} instead of \bigstrut, but I do not like the asymmetric vertical look that it produces when \hlines are involved. With \bigstrut, you can fully control the space.

\documentclass[a4paper,12pt]{article}

\usepackage{amsmath}
\usepackage{amssymb}
\def\bigstrut{\rule[-1ex]{0pt}{3.5ex}}
\begin{document}

\newcommand{\vnull}{\boldsymbol{0}}
\newcommand{\vK}{\boldsymbol{K}}
\newcommand{\vN}{\boldsymbol{N}}
\newcommand{\vT}{\boldsymbol{T}}
\newcommand{\vD}{\boldsymbol{D}}
\begin{equation*}
  \left(
    \begin{array}{l|l|l}
      \bigstrut\vK & \vN^\top & \vT^\top \\
      \hline
      - \bigstrut\rho \vD(\mathcal{A}_\nu) \vN & \vD(\mathcal{I}_\nu) & \vnull\\
      \hline
      - \bigstrut\rho \vD(\mathcal{A}_t) \vT & \vnull
                     & \vD(\mathcal{I}_t^+ \cup \mathcal{I}_t^-)
    \end{array}
  \right)
\end{equation*}

\end{document} 

or if \def\bigstrut{\rule[-2ex]{0pt}{5ex}}, then

For comparison here is the result of using \renewcommand\arraystretch{1.8} with no \bigstrut added. I don't like it as much: