Does anyone know how I could write this block matrix with a LaTeX code ? For now, this is a figure I did on photoshop… And I would like it to be an equation to have a better resolution.
[Tex/LaTex] Block matrices with LaTeX
blockmatrices
Related Solutions
This is one way:
\documentclass[a4paper,journal]{IEEEtran}
\usepackage{amsmath}
\begin{document}
\[
\begin{bmatrix}
\frac{I}{\mathrm{O}}\frac{\mathrm{O}}{\mathrm{O}}
\end{bmatrix}
\begin{bmatrix}
\frac{x}{u}
\end{bmatrix} =
\begin{bmatrix}
\frac{A}{C}\frac{B}{D}
\end{bmatrix}
\begin{bmatrix}
\frac{x}{u}
\end{bmatrix} +
\begin{bmatrix}
\frac{\mathrm{O}}{-y}
\end{bmatrix}
\]
%
\[
\left[
\frac{I}{\mathrm{O}}\frac{\mathrm{O}}{\mathrm{O}}
\right]
\left[
\frac{x}{u}
\right] =
\left[
\frac{A}{C}\frac{B}{D}
\right]
\left[
\frac{x}{u}
\right] +
\left[
\frac{\mathrm{O}}{-y}
\right]
\]
\end{document}
Instead of dynamically varying brackets (\left[ and \right]), you may use fixed size brackets like \Bigg[ and \Bigg] provided by amsmath.
The following is not really eye-candy, but it's probably what you're after:
\documentclass{article}
\usepackage{mathtools}% http://ctan.org/pkg/mathtools
\begin{document}
\[
D =
\underbracket{\begin{pmatrix}
D_1 & 0 & 0 & & & \\
0 & \ddots & & & {\textrm{\huge 0}} & \\
0 & 0 & D_n & & & \\
& & & & & \\
& \textrm{\huge 0} & & & {\textrm{\huge 0}} & \\
& & & & & \\
\end{pmatrix}}_N
\]
\[
D= \underbracket[.4pt]{\left(\begin{array}{@{}c@{\quad}c}
\underbracket[.4pt]{\begin{array}{ccc}
D_1 & \vphantom{\ddots}0 & 0 \\
0 & \ddots & 0 \\
0 & \vphantom{\ddots}0 & D_n
\end{array}}_{n} & \text{\huge 0} \\
\\
\text{\huge 0} & \text{\huge 0}
\end{array}\right)}_{N}
\]
\end{document}
The use of \vphantom ensure that the row height for the "inner matrix" is similar across all rows (without actually printing \ddots).
I went with a more traditional approach (using array), rather than pmatrix. The advantage is that you have control over the alignment.
Best Answer