# Matrix with its name on it, of huge size

How can I replace the original matrix [L] which is of normal size with a huge one, like this figure shows (the red result is what I want):

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One option:

\documentclass{article}
\usepackage{amsmath}

\begin{document}

$\begin{bmatrix} \delta_{1} \\ \delta_{2} \\ \vdots \\ \delta_{M} \\ \end{bmatrix} = \begin{bmatrix} \qquad\qquad \\ \\ \raisebox{0pt}[0pt][0pt]{\Huge L} \\ \\ \end{bmatrix}_{M\times M} \begin{bmatrix} v_{1} \\ v_{2} \\ \vdots \\ v_{M} \\ \end{bmatrix}$

\end{document}

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Thanks, @Gonzalo Medina ! –  C. Wang May 4 '14 at 16:00
@C.Wang I've improved the answer in my edit. –  Gonzalo Medina May 4 '14 at 16:16

If you want the same size of the brackets, use a \vphantom:

\documentclass{article}
\usepackage{amsmath}

\begin{document}

$\begin{bmatrix} \delta_{1} \\ \delta_{2} \\ \vdots \\ \delta_{M} \\ \end{bmatrix} = \left[ \vphantom{% \begin{matrix} v_{1} \\ v_{2} \\ \vdots \\ v_{M} \\ \end{matrix}% } \quad\begin{gathered}\text{\Huge L}\end{gathered}\quad \right]_{M\times M} \begin{bmatrix} v_{1} \\ v_{2} \\ \vdots \\ v_{M} \\ \end{bmatrix}$

\end{document}

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Out of curiosity (and excuse my ignorance), but why do you switch to text mode before issuing \Huge, only to re-enter math mode with $L$? –  Sean Allred May 4 '14 at 16:57
@SeanAllred \Huge in math mode is illegal. –  egreg May 4 '14 at 18:18
\includegraphics{simpler-than-expected} –  Sean Allred May 4 '14 at 18:23

This way?

\documentclass{article}

\usepackage[showframe, nomarginpar, textwidth = 16cm]{geometry}
\usepackage{mathtools}
\usepackage{graphics}

\begin{document}

$\begin{bmatrix} δ_1\\δ_{2} \\ \vdots \\ δ_M \end{bmatrix} = \begin{bmatrix} \vphantom{\begin{matrix} δ_1 & & δ_M \\δ_{2} \\ \vdots \\ δ_M \end{matrix}}\scalebox{2.5}{\enspace L \enspace} \end{bmatrix}_{M× M} \begin{bmatrix} v_1\\v_{2} \\ \vdots \\ v_M \end{bmatrix} ,$

\end{document}

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Concisely, with stacks.

\documentclass{article}
\usepackage{stackengine}
\stackMath
\setstackgap{L}{1.3\baselineskip}
\begin{document}
\savestack{\tmp}{\Huge $L$}
$$\left[\addstackgap{\Centerstack{\delta_1 \delta_2 {\vdots} \delta_M}}\right] = \left[\addstackgap[2.5\baselineskip]{\smash{~~~~~~\raisebox{-.3\ht\tmpcontent}{\tmp}~~~~~~}}\right]_{M\times M} \left[\addstackgap{\Centerstack{v_1 v_2 {\vdots} v_M}}\right]$$
\end{document}

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