There are 2 matrices and the result of their product:
$X=\begin{bmatrix}a & b \\ c & d\end{bmatrix}$
$D=\begin{bmatrix}1 & 0 & 0 & 0 & 0 & 1\\ 0 & 0 & 1 & 0 & 0 & 0\end{bmatrix}$
$X \cdot D=\begin{bmatrix}a & 0 & b & 0 & 0 & a\\ c & 0 & d & 0 & 0 & c\end{bmatrix}$
The desired result looks like this:
My question: are there alternative, simpler operators that do the desired transformation?
My attempt: I first vectorized the original result, then "cut and stitched" in a new way [https://math.stackexchange.com/a/3122442/656085]:
https://dropmefiles.com/avpwH - here is the file from Mathcad Prime 8
Partition $D$ into 8 column vectors, so $XD$ is just$[Xv_1, ... , Xv_8]$ $$X \begin{bmatrix}e\\f\end{bmatrix}$$ is the column vector $e$ column 1 of $X$+$f$ column 2 of $X.$