ftriang – IQClab

The function $A=ftriang(A_1,A_2,A_3,type)$ constructs either one of the following triangular matrices:

For $type=1$ : $\left(\!\!\begin{array}{cc}A_1&A_2\\0&A_3\end{array}\!\!\right)$
For $type=2$ : $\left(\!\!\begin{array}{cc}0&A_1\\A_2&A_3\end{array}\!\!\right)$
For $type=3$ : $\left(\!\!\begin{array}{cc}A_1&0\\A_2&A_3\end{array}\!\!\right)$
For $type=4$ : $\left(\!\!\begin{array}{cc}A_1&A_2\\A_3&0\end{array}\!\!\right)$