IndicatorZero

class odl.solvers.functional.default_functionals.IndicatorZero(*args, **kwargs)

Bases: odl.solvers.functional.functional.Functional

The indicator function of the singleton set {0}.

The function has a constant value if the input is zero, otherwise infinity.

Attributes

adjoint

Adjoint of this operator (abstract).

constant

The constant value of the functional if x=0.

convex_conj

The convex conjugate functional.

domain

Set of objects on which this operator can be evaluated.

grad_lipschitz

Lipschitz constant for the gradient of the functional.

gradient

Gradient operator of the functional.

inverse

Return the operator inverse.

is_functional

True if this operator’s range is a Field.

is_linear

True if this operator is linear.

proximal

Return the proximal factory of the functional.

range

Set in which the result of an evaluation of this operator lies.

Methods

_call(self, x)	Apply the functional to the given point.
bregman(self, point, subgrad)	Return the Bregman distance functional.
derivative(self, point)	Return the derivative operator in the given point.
norm(self[, estimate])	Return the operator norm of this operator.
translated(self, shift)	Return a translation of the functional.

__init__(self, space, constant=0)

Initialize a new instance.

Parameters

spaceLinearSpace

Domain of the functional.

constantelement in domain.field, optional

The constant value of the functional

Examples

>>> space = odl.rn(3)
>>> func = IndicatorZero(space)
>>> func([0, 0, 0])
0
>>> func([0, 0, 1])
inf

>>> func = IndicatorZero(space, constant=2)
>>> func([0, 0, 0])
2