I need to drive the sub-differential of L2 norm of a vector. Would someone can help me with this ?
What is the sub-differential of L2 norm?
3
$\begingroup$
abstract-algebra
optimization
convex-analysis
-
0Why is it marked as off topic? I don't understand, finding derivative and integrals are on topic and finding sub-differential is off-topic. Down voting because of lack of context make sense but why put on hold as off-topic? – 2017-01-04
-
0Wikipedia shows the derivative for $x\neq 0$: $x / ||x||$. For $x=0$, $0$ is a subdifferential (readily verified with the definition). – 2017-01-04