from typing import TYPE_CHECKING
import numpy as np
from pylops.utils.typing import NDArray
from pyproximal.projection.AffineSet import AffineSetProj
from pyproximal.ProxOperator import ProxOperator, _check_tau
if TYPE_CHECKING:
from pylops.linearoperator import LinearOperator
[docs]
class AffineSet(ProxOperator):
r"""Affine set proximal operator.
Proximal operator of an Affine set: :math:`\{ \mathbf{x} : \mathbf{Opx}=\mathbf{b} \}`.
Parameters
----------
Op : :obj:`pylops.LinearOperator`
Linear operator
b : :obj:`numpy.ndarray`
Data vector
niter : :obj:`int`
Number of iterations of iterative scheme used to compute the projection.
Notes
-----
As the Affine set is an indicator function, the proximal operator corresponds to
its orthogonal projection (see :class:`pyproximal.projection.AffineSetProj` for
details.
"""
# guarantee that Op is a LinearOperator as in
# ProxOperator it could be None
Op: "LinearOperator"
def __init__(self, Op: "LinearOperator", b: NDArray, niter: int) -> None:
super().__init__(Op, False)
self.b = b
self.niter = niter
self.affine = AffineSetProj(self.Op, self.b, self.niter)
def __call__(self, x: NDArray) -> bool:
if np.allclose(self.Op.matvec(x), self.b):
return True
else:
return False
@_check_tau
def prox(self, x: NDArray, tau: float) -> NDArray:
return self.affine(x)
PyProximal