# print the rows of a matrix in two different sections in order to prevent the elements from mixing together

As you see in the following picture I have a 4x4 matrix and the elements are so lengthy that they will not fit in a single line of an A4 paper.
In fact this equation is printed in a book that I'm translating. I'm not familiar with LateX and I'm just typing mathematical expression with LaTex in Mathtype. So I can only use amsmath package and math-mode codes

The question is how can I create the exact shape of equation in my LaTex code?
what I have done so far, is the following code:

\begin{bmatrix}
. & . & . & .\\
. & . & . & .\\
. & . & . & .\\
. & . & . & .
\end{bmatrix}


I know how to write each element of the matrix. In fact I know what to write instead of dots
I know for seperating elements of matrix in a single row, & should be used and to go to the next row, we should use \\
Also I'm familiar with \cdots, ldots and etc.
But I don't know how to rearrange the elements exactly like the picture and prevent them from mixing up together?

Edit:

\begin{align}
T_4 &= \langle \underline{k}\,.\,\underline{k}^{*^T} \rangle=
\left\langle
\begin{bmatrix}
\left|k_1\right|^2 & k_1k_2^* & k_1k_3^* & k_1k_4^*\\
k_2k_1^* & \left|k_2\right|^2 & k_2k_3^* & k_2k_4^*\\
k_3k_1^* & k_3k_2^* & \left|k_3\right|^2 & k_3k_4^*\\
k_4k_1^* & k_4k_2^* & k_4k_3^* & \left|k_4\right|^2
\end{bmatrix}
\right\rangle
\\
&=\frac{1}{2}
\begin{split}
\left[\begin{matrix}
\langle|S_{XX}+S_{YY}|^2\rangle &
\langle(S_{XX}+S_{YY})(S_{XX}-S_{YY})^*\rangle &\\
\langle(S_{XX}-S_{YY})(S_{XX}+S_{YY})^*\rangle &
\langle|S_{XX}-S_{YY}|^2\rangle & \cdots\cdots\\
\langle(S_{XY}+S_{YX})(S_{XX}+S_{YY})^*\rangle&
\langle(S_{XY}+S_{YX})(S_{XX}-S_{YY})^*\rangle & \cdots\cdots\\
\langle j(S_{XY}-S_{YX})(S_{XX}+S_{YY})^*\rangle &
\langle j(S_{XY}-S_{YX})(S_{XX}-S_{YY})^*\rangle &
\end{matrix}\right.\\
\left.\begin{matrix}
& \langle(S_{XX}+S_{YY})(S_{XY}+S_{YX})^*\rangle
& \langle -j(S_{XX}+S_{YY})(S_{XY}-S_{YX})^*\rangle\\
\cdots\cdots& \langle(S_{XX}-S_{YY})(S_{XY}+S_{YX})^*\rangle
& \langle -j(S_{XX}-S_{YY})(S_{XY}-S_{YX})^*\rangle\\
\cdots\cdots& \langle|S_{XY}+S_{YX}|^2\rangle
& \langle-j(S_{XY}+S_{YX})(S_{XY}-S_{YX})^*\rangle\\
& \langle j(S_{XY}-S_{YX})(S_{XY}+S_{YX})^*\rangle
& \langle|S_{XY}-S_{YX}|^2\rangle
\end{matrix}\right]
\end{split}
\end{align}


It is displayed like this math.stackexchange.com

• A minimal (non)working code would be nice to save us the tedium of typing the whole formulae. Could you post one so we can play with it? Aug 9, 2015 at 12:34
• It is a symmetric matrix. You don't need to type out every element. As you can see it takes quite some attention to see that it is a symmetric matrix which can be pretty obvious if you typeset it so. And what is the LR bracket operation, inner product? Aug 9, 2015 at 13:41
• @percusse LR bracket is for ensemble averaging Aug 9, 2015 at 13:51
• @Bernard I'll start now to try out LaRiFaRi's answer, then I will post the code here if I need more help and save you the tedium of typing the whole question Aug 9, 2015 at 13:54
• @percusse: it isn't really symmetric, as I can see it. Aug 9, 2015 at 14:04

% arara: pdflatex
$% or if you want it numberd. \begin{split} \left[\begin{matrix} . & . &\\ . & . & \cdots\cdots\\ . & . & \cdots\cdots\\ . & . & \end{matrix}\right.\\ \left.\begin{matrix} & . & .\\ \cdots\cdots& . & .\\ \cdots\cdots& . & .\\ & . & . \end{matrix} \right] \end{split}$