Standard notation for sum of vector elements?

$\sum_{i=1}^n v_i$ is the most widely accepted and understood notation.

If you use the euclidean 1-norm and you want the sum of the absolute values of the entries of $\vec{v}$ (or $v_i\geq 0$ ) you can take $\| \vec{v}\|_1$. Otherwise you can use $sum\{\vec{v} \}$ or $trace( diag\{ \vec{v}\})$. But I guess $sum\{\vec{v}\}$ would be the more "standard" notation.