pyproximal.L0Ball

class pyproximal.L0Ball(radius: Union[int, Callable[[int], int]])

\(L_0\) ball proximal operator.

Proximal operator of the L0 ball: \(L0_{r} = \{ \mathbf{x}: ||\mathbf{x}||_0 \leq r \}\).

Parameters

radiusint or func, optional

Radius. This can be a constant number or a function that is called passing a counter which keeps track of how many times the prox method has been invoked before and returns a scalar radius to be used.

Notes

As the L0 ball is an indicator function, the proximal operator corresponds to its orthogonal projection (see pyproximal.projection.L0BallProj for details.

Methods

__init__(radius)
affine_addition(v)	Affine addition
chain(g)	Chain
grad(x)	Gradient of the Moreau envelope of the function.
postcomposition(sigma)	Postcomposition
precomposition(a, b)	Precomposition
prox(*args, **kwargs)
proxdual(**kwargs)

Examples using pyproximal.L0Ball

Group sparsity

Group sparsity

IHT, ISTA, FISTA, AA-ISTA, and TWIST for Compressive sensing

IHT, ISTA, FISTA, AA-ISTA, and TWIST for Compressive sensing