if $\displaystyle C = LDL^{-1}$ , where $\displaystyle D$ is the Diagonal Matrix, how do I rearrange the expression to have $\displaystyle C^{-1}$ in terms of $\displaystyle L, L^{-1}$ and $\displaystyle D$. (also, what specific diagonal matrix can I give? is the $\displaystyle I_n$ ok?)

Many Thanks