# Proximal Operators (sigpy.prox)¶

This module contains an abstraction class Prox for proximal operators, and provides commonly used proximal operators, including soft-thresholding, l1 ball projection, and box constraints.

## The Proximal Operator Class¶

 sigpy.prox.Prox Abstraction for proximal operator.

## Prox Manipulation¶

 sigpy.prox.Conj Returns the proximal operator for the convex conjugate function. sigpy.prox.Stack Stack outputs of proximal operators. sigpy.prox.UnitaryTransform Unitary transform input space.

## Basic Proxs¶

 sigpy.prox.NoOp Proximal operator for empty function. sigpy.prox.BoxConstraint Box constraint proximal operator. sigpy.prox.L1Proj Proximal operator for l1 norm projection. sigpy.prox.L1Reg Proximal operator for l1 regularization. sigpy.prox.L2Proj Proximal operator for l2 norm projection. sigpy.prox.L2Reg Proximal operator for l2 regularization. sigpy.prox.LInfProj Proximal operator for l-infinity ball projection. sigpy.prox.PsdProj Proximal operator for positive semi-definite matrices.