Source code for nifty8.operators.mask_operator
# This program is free software: you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation, either version 3 of the License, or
# (at your option) any later version.
#
# 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.
#
# You should have received a copy of the GNU General Public License
# along with this program. If not, see <http://www.gnu.org/licenses/>.
#
# Copyright(C) 2013-2019 Max-Planck-Society
#
# NIFTy is being developed at the Max-Planck-Institut fuer Astrophysik.
import numpy as np
from ..domain_tuple import DomainTuple
from ..domains.unstructured_domain import UnstructuredDomain
from ..field import Field
from .linear_operator import LinearOperator
[docs]
class MaskOperator(LinearOperator):
"""Implementation of a mask response
Takes a field, applies flags and returns the values of the field in a
:class:`UnstructuredDomain`.
Parameters
----------
flags : :class:`nifty8.field.Field`
Is converted to boolean. Where True, the input field is flagged.
"""
[docs]
def __init__(self, flags):
if not isinstance(flags, Field):
raise TypeError
self._domain = DomainTuple.make(flags.domain)
self._flags = np.logical_not(flags.val)
self._target = DomainTuple.make(UnstructuredDomain(self._flags.sum()))
self._capability = self.TIMES | self.ADJOINT_TIMES
def mask(x):
return x[self._flags]
self._jax_expr = mask
[docs]
def apply(self, x, mode):
self._check_input(x, mode)
x = x.val
if mode == self.TIMES:
res = x[self._flags]
return Field(self.target, res)
res = np.empty(self.domain.shape, x.dtype)
res[self._flags] = x
res[~self._flags] = 0
return Field(self.domain, res)