Follow

People who know linear algebra: if I said "make a block diagonal from these matrices", would you know what I meant?

How about "augmented matrix"?

And is there a term for when you put one matrix on top of another?

@asvhl great, thanks!

@christianp Sure! If

\[A=\begin{bmatrix}1&2\\3&4\end{bmatrix}\]

and

\[B=\begin{bmatrix}5&6\\7&8\end{bmatrix},\]

then I'd interpret that to mean

\[\text{diag}(A, B)=\begin{bmatrix}1&2&0&0\\3&4&0&0\\0&0&5&6\\0&0&7&8\end{bmatrix}.\]

The notations \((A|B)\), \([A|B]\), or \(\begin{bmatrix}A&B\end{bmatrix}\) would read as an augmented matrix to me. I don't know of a better way to write concatenating rows other than

\[\begin{bmatrix}A\\B\end{bmatrix},\]

unfortunately!

@neilbickford thanks!

So that wouldn't be the kind of augmented matrix you're used to?

@maralorn nice, thanks

asvhl@asvhl@mastodon.mit.edu@christianp I think the term for putting one matrix on top of another is "stacking". At least in sagemath, you can do that via M1.stack(M2), just like you can put M1 and M2 next to each other using M1.augment(M2)