Subgradient
= Subgradient
A subgradient of a <convex function> $f$ at $x$ is a vector $g$ such that $f(y)\geq f(x)+g^T(y-x)$ for every $y$ in the domain.
= Subgradient
A subgradient of a <convex function> $f$ at $x$ is a vector $g$ such that $f(y)\geq f(x)+g^T(y-x)$ for every $y$ in the domain.