[Tex/LaTex] How to Specify two level row and column labels of a matrix by braces

matricestikz-pgf

I'm trying to write the following matrices.
enter image description here

I used the following code (given by Caramdir)

\documentclass{article}
% Load TikZ
\usepackage{tikz}
\usetikzlibrary{matrix,decorations.pathreplacing,calc}
% Set various styles for the matrices and braces. It might pay off to fiddle around     with the values a little bit
 \pgfkeys{tikz/mymatrixenv/.style={decoration=brace,every left delimiter/.style=    {xshift=3pt},every right delimiter/.style={xshift=-3pt}}}
 \pgfkeys{tikz/mymatrix/.style={matrix of math nodes,left delimiter=[,right delimiter=    {]},inner sep=2pt,column sep=1em,row sep=0.5em,nodes={inner sep=0pt}}}
 \pgfkeys{tikz/mymatrixbrace/.style={decorate,thick}}
 \newcommand\mymatrixbraceoffseth{0.5em}
 \newcommand\mymatrixbraceoffsetv{0.2em}

% Now the commands to produce the braces. (I'll explain below how to use them.)
\newcommand*\mymatrixbraceright[4][m]{
\draw[mymatrixbrace] ($(#1.north west)!(#1-#3-1.south west)!(#1.south west)-    (\mymatrixbraceoffseth,0)$)
    -- node[left=2pt] {#4} 
    ($(#1.north west)!(#1-#2-1.north west)!(#1.south west)-(\mymatrixbraceoffseth,0)$);
}
 \newcommand*\mymatrixbraceleft[4][m]{
 \draw[mymatrixbrace] ($(#1.north east)!(#1-#2-1.north east)!(#1.south east)+    (\mymatrixbraceoffseth,0)$)
    -- node[right=2pt] {#4} 
     ($(#1.north east)!(#1-#3-1.south east)!(#1.south east)+    (\mymatrixbraceoffseth,0)$);
}
\newcommand*\mymatrixbracetop[4][m]{
\draw[mymatrixbrace] ($(#1.north west)!(#1-1-#2.north west)!(#1.north east)+(0,\mymatrixbraceoffsetv)$)
    -- node[above=2pt] {#4} 
    ($(#1.north west)!(#1-1-#3.north east)!(#1.north east)+(0,\mymatrixbraceoffsetv)$);
}
\newcommand*\mymatrixbracebottom[4][m]{
\draw[mymatrixbrace] ($(#1.south west)!(#1-1-#3.south east)!(#1.south east)-(0,\mymatrixbraceoffsetv)$)
    -- node[below=2pt] {#4} 
    ($(#1.south west)!(#1-1-#2.south west)!(#1.south east)-(0,\mymatrixbraceoffsetv)$);
}

\usepackage{tikz}
\usetikzlibrary{matrix,decorations.pathreplacing}

\begin{document}


 \[
 \begin{tikzpicture}[mymatrixenv]
 \matrix[mymatrix] (m)  {
    a & b & c & d & e & f \\
    g & h & i & j & k & l\\
    l & m & n & o & p & o \\
    \hline \\
    q & r & s & t & u & v \\
    w & x & y & z & a & b \\
    c & d & e & f & g & h \\
  };
  \mymatrixbraceright{1}{3}{$E_1$}
  \mymatrixbraceright{5}{7}{$E_2$}
  \mymatrixbracetop{1}{3}{$E_1$}
  \mymatrixbracetop{4}{6}{$E_2$}
\end{tikzpicture}
\]

\end{document}

Output

It's really nice but still it doesn't serve my purpose. Any help in this regard will be highly appreciated. Thanks

Best Answer

Here is my version. With some tweaking, it can be made efficient. 

\begin{tikzpicture}
\matrix [matrix of math nodes,left delimiter=(,right delimiter=),row sep=0.5cm,column sep=0.5cm] (m) {
1&2&3&4 \\
1&2&3&4 \\
1&2&3&4 \\
1&2&3&4 \\};
\draw[dashed] ($0.5*(m-1-2.north east)+0.5*(m-1-3.north west)$) --
      ($0.5*(m-4-2.south east)+0.5*(m-4-3.south west)$);
\draw[dashed] ($0.5*(m-2-1.south west)+0.5*(m-3-1.north west)$) --
      ($0.5*(m-2-4.south east)+0.5*(m-3-4.north east)$);
\node[above=10pt of m-1-1] (top-1) {a};
\node[above=10pt of m-1-2] (top-2) {b};
\node[above=10pt of m-1-3] (top-3) {c};
\node[above=10pt of m-1-4] (top-4) {d};

\node[left=12pt of m-1-1] (left-1) {$\alpha$};
\node[left=12pt of m-2-1] (left-2) {$\beta$};
\node[left=12pt of m-3-1] (left-3) {$\gamma$};
\node[left=12pt of m-4-1] (left-4) {$\delta$};

\node[rectangle,above delimiter=\{] (del-top-1) at ($0.5*(top-1.south) +0.5*(top-2.south)$) {\tikz{\path (top-1.south west) rectangle (top-2.north east);}};
\node[above=10pt] at (del-top-1.north) {$A$};
\node[rectangle,above delimiter=\{] (del-top-2) at ($0.5*(top-3.south) +0.5*(top-4.south)$) {\tikz{\path (top-3.south west) rectangle (top-4.north east);}};
\node[above=10pt] at (del-top-2.north) {$B$};

\node[rectangle,left delimiter=\{] (del-left-1) at ($0.5*(left-1.east) +0.5*(left-2.east)$) {\tikz{\path (left-1.north east) rectangle (left-2.south west);}};
\node[left=10pt] at (del-left-1.west) {$C$};
\node[rectangle,left delimiter=\{] (del-left-2) at ($0.5*(left-3.east) +0.5*(left-4.east)$) {\tikz{\path (left-3.north east) rectangle (left-4.south west);}};
\node[left=10pt] at (del-left-2.west) {$D$};

\end{tikzpicture}

The result is

matrix

Answer to comment : One way to incorporate the math signs is to place everything in nodes. You could also place the matrices within boxes and include them in an equation, but this approach is tricky and delicate. As an example, just insert the following code after my initial code, before the \end{tikzpicture} :

\node[right=of m] (op) {$\times$};

\matrix [right=of op,matrix of math nodes,left delimiter=(,right delimiter=),row sep=0.5cm,column sep=0.5cm] (n) {
1&2 \\
1&2 \\
};

\node[above=10pt of n-1-1]  {a};
\node[above=10pt of n-1-2]  {b};

\node[left=12pt of n-1-1]  {$\alpha$};
\node[left=12pt of n-2-1]  {$\beta$};
Related Question