<s>[INST] formular for sum of column in a Matrix I have a trivial problem. I need to create a vector, which has the sum of the columns in a AxB matrix. What would be the mathematical formula for that?
Thank you
 [/INST] Hint: The following examples might be helpful.
\begin{align*}
\begin{pmatrix}a&b&c\\d&e&f\end{pmatrix}
\begin{pmatrix}1\\1\\1\end{pmatrix}
&=\begin{pmatrix}a+b+c\\d+e+f\end{pmatrix}\\
\begin{pmatrix}1&1\end{pmatrix}\begin{pmatrix}a&b&c\\d&e&f\end{pmatrix}
&=\begin{pmatrix}a+d&b+e&c+f\end{pmatrix}
\end{align*}
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