cr.sparse.opt.indicator_singleton

cr.sparse.opt.indicator_singleton(c)

Returns an indicator function for a singleton set $C=\{c\}$

Parameters

c (jax.numpy.ndarray) – An array

Returns

An indicator function

Let $C$ be a singleton convex set $\{c\}$ where $c\in {\mathbb{R}}^n$.

We implement its indicator function as:

(1)$$\begin{array}{r}I(x)=\{\begin{array}{ll}0& \text{if }x=c\\ \mathrm{\infty }& \text{if }x\ne c\end{array}\end{array}$$

Note

The implementation broadcasts $c$ to the shape of $x$ before making the comparison.

Thus if $c==4$ and $x=[4,4,4,4]$, then $I(x)=0$.