Possible Duplicate:
Highlight elements in the matrix
I have a big matrix as follows:
\documentclass{article}
\usepackage{amsmath}
\begin{document}
\[
\tilde{M}_{R+1,N}=
\begin{pmatrix}
r_{1,(1)}^{(1)},r_{1,(2)}^{(1)} \cdots, r_{1,(n)}^{(1)}, r_{2,(1)}^{(1)}, r_{2,(2)}^{(1)}, \cdots, r_{2,(n)}^{(1)}, \cdots, r_{m,(1)}^{(1)}, r_{m,(2)}^{(1)}, \cdots, r_{m,(n)}^{(1)}\\
r_{1,(1)}^{(2)},r_{1,(2)}^{(2)} \cdots, r_{1,(n)}^{(2)}, r_{2,(1)}^{(2)}, r_{2,(2)}^{(2)}, \cdots, r_{2,(n)}^{(2)}, \cdots, r_{m,(1)}^{(2)}, r_{m,(2)}^{(2)}, \cdots, r_{m,(n)}^{(2)}\\
\vdots \\
r_{1,(1)}^{(R)},r_{1,(2)}^{(R)} \cdots, r_{1,(n)}^{(R)}, r_{2,(1)}^{(R)}, r_{2,(2)}^{(R)}, \cdots, r_{2,(n)}^{(R)}, \cdots, r_{m,(1)}^{(R)}, r_{m,(2)}^{(R)}, \cdots, r_{m,(n)}^{(R)} \\
r_{1,(1)}^{(0)},r_{1,(2)}^{(0)} \cdots, r_{1,(n)}^{(0)}, r_{2,(1)}^{(0)}, r_{2,(2)}^{(0)}, \cdots, r_{2,(n)}^{(0)}, \cdots, r_{m,(1)}^{(0)}, r_{m,(2)}^{(0)}, \cdots, r_{m,(n)}^{(0)}
\end{pmatrix}
\]
\end{document}
Resulting in:
Now I want to draw several boxes on this big matrix. The first box contains elements from the first n columns and all rows; the second box contains elements from the next n columns and all rows, and so on. When I use \boxed command, it can only take characters that are 'together'.
How can I make such boxes in the math environment that contain "non-together" characters?
tikzis used for this. See for example http://tex.stackexchange.com/questions/40028/highlight-elements-in-the-matrix or http://tex.stackexchange.com/questions/69726/tikz-marking-several-blocks-in-a-matrix – JLDiaz Jan 06 '13 at 00:32&instead of a,to get a real (multi-columned) matrix instead of a vector (a single-columned matrix). – Qrrbrbirlbel Jan 06 '13 at 00:35