"""Information operator returning a projection of the right-hand-side."""
import numpy as np
import probnum # pylint: disable="unused-import"
from ._linear_solver_information_op import LinearSolverInformationOp
class ProjectedResidualInformationOp(LinearSolverInformationOp):
r"""Projected residual information operator.
Obtain information about a linear system by projecting the residual
:math:`b-Ax_{i-1}` onto a given action :math:`s_i` resulting in :math:`s_i
\mapsto s_i^\top r_{i-1} = s_i^\top (b - A x_{i-1}) = s_i^\top
A (x - x_{i-1})`.
"""