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# the Free Software Foundation, either version 3 of the License, or
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#
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
# GNU General Public License for more details.
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# You should have received a copy of the GNU General Public License
# along with this program. If not, see .
#
# Copyright(C) 2013-2021 Max-Planck-Society
#
# NIFTy is being developed at the Max-Planck-Institut fuer Astrophysik.
from ..operators.endomorphic_operator import EndomorphicOperator
from ..operators.inversion_enabler import InversionEnabler
from ..operators.sampling_enabler import SamplingEnabler
from ..operators.sandwich_operator import SandwichOperator
def WienerFilterCurvature(R, N, S, iteration_controller=None,
iteration_controller_sampling=None):
"""The curvature of the WienerFilterEnergy.
This operator implements the second derivative of the
WienerFilterEnergy used in some minimization algorithms or
for error estimates of the posterior maps. It is the
inverse of the propagator operator.
Parameters
----------
R : LinearOperator
The response operator of the Wiener filter measurement.
N : EndomorphicOperator
The noise covariance.
S : EndomorphicOperator
The prior signal covariance.
iteration_controller : IterationController
The iteration controller to use during numerical inversion via
ConjugateGradient.
iteration_controller_sampling : IterationController
The iteration controller to use for sampling.
Note
----
If samples shall be drawn from this operator, `N` and `S` have to implement
`draw_sample()`.
"""
if not isinstance(N, EndomorphicOperator):
raise TypeError
if not isinstance(S, EndomorphicOperator):
raise TypeError
M = SandwichOperator.make(R, N.inverse)
Sinv = S.inverse
if iteration_controller_sampling is not None:
op = SamplingEnabler(M, Sinv, iteration_controller_sampling, Sinv)
else:
op = M + Sinv
return InversionEnabler(op, iteration_controller, Sinv)