I tried that \middle
, \,\middle|\,
and \mathrel{\Big|}
. I read How to automatically scale `\mid` within delimiters and
\usepackage{mleftright}
\usepackage{amsmath}
\begin{document}
\begin{equation}
MASE = \frac{1}{n} \mathrel{\Big|} \sum_{i = 1}^{n} \hat{\Sigma}^{-1/2}\begin{pmatrix}
y_{ci} - \hat{y}_{ci}\\
y_{ri} - \hat{y}_{ri}
\end{pmatrix} \mathrel{\Big|},
\label{eq:mase}
\end{equation}
\end{document}
Best Answer
I believe you want the absolute value:
I've often seen
\mid
misused as vertical bar; it indeed typesets a vertical bar, but considered as a binary relation.For the absolute value you should use
\lvert
and\rvert
, which can be abbreviated as\left|
and\right|
when automatic sizing is desired.