Collision operator  $\vec{C}$:
\begin{equation*}
\vec{C}\left(\vec{f} \right) = \matr{M}^{-1}_2 \matr{S} \left(\vec{\mu}_2^{(eq)} - \matr{M}_2\vec{f} \right),
\end{equation*}
where
$$
	\matr{S} = \mathrm{diag}(\oA,\oB,\oC,\oD,\oE,\oF,\oG,\oH,\oI),
$$
$\oA,\oB,\dots,\oI \in \left(0,2\right)$.

Matrix $\matr{M}_2$ corresponds to the transformation matrix to the raw moment basis defined by
\begin{equation*}
 \vec{\mu}_2 = \begin{pmatrix}
	m_{(0,0)} \\
	m_{(1,0)} \\
	m_{(0,1)} \\
	m_{(1,1)} \\
	m_{(2,0)} + m_{(0,2)} \\
	m_{(2,0)} - m_{(0,2)} \\
	m_{(2,1)} \\
	m_{(1,2)} \\
	m_{(2,2)}
\end{pmatrix},
\end{equation*}
and is given by
\input{\path/d2q9_mrt2_matM}

The equilibrium moments $\vec{\mu}^{(eq)}_2$ are defined by
\begin{equation*}
\vec{\mu}^{(eq)}_2 = \matr{M}_2 \matr{M}^{-1} \vec{\mu}^{(eq)},
\end{equation*}
i.e.,
\input{\path/d2q9_mrt2_eq}
