# 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 ..operators.null_operator import NullOperator
from .model import Model
class Constant(Model):
"""A model with a constant (multi-)field as value.
Parameters
----------
position : Field or MultiField
The current position in parameter space.
constant : Field
The value of the model.
Notes
-----
Since there is no model-function associated:
- Position has no influence on value.
- The Jacobian is a null matrix.
"""
def __init__(self, position, constant):
super(Constant, self).__init__(position)
self._constant = constant
self._value = self._constant
self._jacobian = NullOperator(position.domain, constant.domain)
def at(self, position):
return self.__class__(position, self._constant)