# 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 . # # Copyright(C) 2013-2018 Max-Planck-Society # # NIFTy is being developed at the Max-Planck-Institut fuer Astrophysik # and financially supported by the Studienstiftung des deutschen Volkes. from __future__ import absolute_import, division, print_function from ..compat import * from ..domain_tuple import DomainTuple from ..field import Field from ..multi.multi_field import MultiField from ..operators.linear_operator import LinearOperator class NullOperator(LinearOperator): """Operator corresponding to a matrix of all zeros. Parameters ---------- domain : DomainTuple or MultiDomain input domain target : DomainTuple or MultiDomain output domain """ def __init__(self, domain, target): from ..sugar import makeDomain self._domain = makeDomain(domain) self._target = makeDomain(target) @staticmethod def _nullfield(dom): if isinstance(dom, DomainTuple): return Field.full(dom, 0) else: return MultiField.full(dom, 0) def apply(self, x, mode): self._check_input(x, mode) if mode == self.TIMES: return self._nullfield(self._target) return self._nullfield(self._domain) @property def domain(self): return self._domain @property def target(self): return self._target @property def capability(self): return self.TIMES | self.ADJOINT_TIMES