In Problems, determine whether the given matrix $\mathbf{A}$ is diagonalizable. If so, find the matrix $\mathbf{P}$ that diagonalizes $\mathbf{A}$ and the diagonal matrix $\mathbf{D}$ such that $\mathbf{D}=\mathbf{P}^{-1} \mathbf{A} \mathbf{P}$.
$$
\left(\begin{array}{rrrr}
4 & 2 & -1 & 4 \\
0 & 2 & 0 & 0 \\
1 & 3 & 2 & 1 \\
0 & 0 & 0 & 2
\end{array}\right)
$$