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Lukas Platz authoredLukas Platz authored
simple_linear_operators.py 12.11 KiB
# 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.
from ..domain_tuple import DomainTuple
from ..domains.unstructured_domain import UnstructuredDomain
from ..field import Field
from ..multi_domain import MultiDomain
from ..multi_field import MultiField
from .endomorphic_operator import EndomorphicOperator
from .linear_operator import LinearOperator
from .. import utilities
class VdotOperator(LinearOperator):
"""Operator computing the scalar product of its input with a given Field.
Parameters
----------
field : Field or MultiField
The field used to build the scalar product with the operator input
"""
def __init__(self, field):
self._field = field
self._domain = field.domain
self._target = DomainTuple.scalar_domain()
self._capability = self.TIMES | self.ADJOINT_TIMES
def apply(self, x, mode):
self._check_mode(mode)
if mode == self.TIMES:
return Field.scalar(self._field.vdot(x))
return self._field*x.local_data[()]
class ConjugationOperator(EndomorphicOperator):
"""Operator computing the complex conjugate of its input.
Parameters
----------
domain: Domain, tuple of domains or DomainTuple
domain of the input field
"""
def __init__(self, domain):
self._domain = DomainTuple.make(domain)
self._capability = self._all_ops
def apply(self, x, mode):
self._check_input(x, mode)
return x.conjugate()
class WeightApplier(EndomorphicOperator):
"""Operator multiplying its input by a given power of dvol.
Parameters
----------
domain: Domain, tuple of domains or DomainTuple
domain of the input field
spaces: list or tuple of int
indices of subdomains for which the weights shall be applied
power: int
the power of to be used for the volume factors
"""
def __init__(self, domain, spaces, power):
from .. import utilities
self._domain = DomainTuple.make(domain)
if spaces is None:
self._spaces = None
else:
self._spaces = utilities.parse_spaces(spaces, len(self._domain))
self._power = int(power)
self._capability = self._all_ops
def apply(self, x, mode):
self._check_input(x, mode)
power = self._power if (mode & 3) else -self._power
return x.weight(power, spaces=self._spaces)
class Realizer(EndomorphicOperator):
"""Operator returning the real component of its input.
Parameters
----------
domain: Domain, tuple of domains or DomainTuple
domain of the input field
"""
def __init__(self, domain):
self._domain = DomainTuple.make(domain)
self._capability = self.TIMES | self.ADJOINT_TIMES
def apply(self, x, mode):
self._check_input(x, mode)
return x.real
class FieldAdapter(LinearOperator):
"""Operator for conversion between Fields and MultiFields.
Parameters
----------
tgt : Domain, tuple of Domain, DomainTuple, dict or MultiDomain:
If this is a Domain, tuple of Domain or DomainTuple, this will be the
operator's target, and its domain will be a MultiDomain consisting of
its domain with the supplied `name`
If this is a dict or MultiDomain, everything except for `name` will
be stripped out of it, and the result will be the operator's target.
Its domain will then be the DomainTuple corresponding to the single
entry in the operator's domain.
name : String
The relevant key of the MultiDomain.
"""
def __init__(self, tgt, name):
from ..sugar import makeDomain
tmp = makeDomain(tgt)
if isinstance(tmp, DomainTuple):
self._target = tmp
self._domain = MultiDomain.make({name: tmp})
else:
self._domain = tmp[name]
self._target = MultiDomain.make({name: tmp[name]})
self._capability = self.TIMES | self.ADJOINT_TIMES
def apply(self, x, mode):
self._check_input(x, mode)
if isinstance(x, MultiField):
return x.values()[0]
else:
return MultiField(self._tgt(mode), (x,))
def __repr__(self):
s = 'FieldAdapter'
dom = isinstance(self._domain, MultiDomain)
tgt = isinstance(self._target, MultiDomain)
if dom and tgt:
s += ' {} <- {}'.format(self._target.keys(), self._domain.keys())
elif dom:
s += ' <- {}'.format(self._domain.keys())
elif tgt:
s += ' {} <-'.format(self._target.keys())
return s
class _SlowFieldAdapter(LinearOperator):
"""Operator for conversion between Fields and MultiFields.
The operator is built so that the MultiDomain is always the target.
Its domain is `tgt[name]`
Parameters
----------
dom : dict or MultiDomain:
the operator's dom
name : String
The relevant key of the MultiDomain.
"""
def __init__(self, dom, name):
from ..sugar import makeDomain
tmp = makeDomain(dom)
if not isinstance(tmp, MultiDomain):
raise TypeError("MultiDomain expected")
self._name = str(name)
self._domain = tmp
self._target = tmp[name]
self._capability = self.TIMES | self.ADJOINT_TIMES
def apply(self, x, mode):
self._check_input(x, mode)
if isinstance(x, MultiField):
return x[self._name]
else:
return MultiField.from_dict({self._name: x},
domain=self._tgt(mode))
def __repr__(self):
return '_SlowFieldAdapter'
def ducktape(left, right, name):
"""Convenience function creating an operator that converts between a
DomainTuple and a MultiDomain.
Parameters
----------
left : None, Operator, or Domainoid
Something describing the new operator's target domain.
If `left` is an `Operator`, its domain is used as `left`.
right : None, Operator, or Domainoid
Something describing the new operator's input domain.
If `right` is an `Operator`, its target is used as `right`.
name : string
The component of the `MultiDomain` that will be extracted/inserted
Notes
-----
- one of the involved domains must be a `DomainTuple`, the other a
`MultiDomain`.
- `left` and `right` must not be both `None`, but one of them can (and
probably should) be `None`. In this case, the missing information is
inferred.
Returns
-------
FieldAdapter or _SlowFieldAdapter
an adapter operator converting between the two (possibly
partially inferred) domains.
"""
from ..sugar import makeDomain
from .operator import Operator
if isinstance(right, Operator):
right = right.target
elif right is not None:
right = makeDomain(right)
if isinstance(left, Operator):
left = left.domain
elif left is not None:
left = makeDomain(left)
if left is None: # need to infer left from right
if isinstance(right, MultiDomain):
left = right[name]
else:
left = MultiDomain.make({name: right})
elif right is None: # need to infer right from left
if isinstance(left, MultiDomain):
right = left[name]
else:
right = MultiDomain.make({name: left})
lmulti = isinstance(left, MultiDomain)
rmulti = isinstance(right, MultiDomain)
if lmulti+rmulti != 1:
raise ValueError("need exactly one MultiDomain")
if lmulti:
if len(left) == 1:
return FieldAdapter(left, name)
else:
return _SlowFieldAdapter(left, name).adjoint
if rmulti:
if len(right) == 1:
return FieldAdapter(left, name)
else:
return _SlowFieldAdapter(right, name)
raise ValueError("must not arrive here")
class GeometryRemover(LinearOperator):
"""Operator which transforms between a structured and an unstructured
domain.
Parameters
----------
domain: Domain, tuple of Domain, or DomainTuple:
the full input domain of the operator.
space: int, optional
The index of the subdomain on which the operator should act.
If None, it acts on all spaces.
Notes
-----
The operator will convert every sub-domain of its input domain to an
UnstructuredDomain with the same shape. No weighting by volume factors
is carried out.
"""
def __init__(self, domain, space=None):
self._domain = DomainTuple.make(domain)
if space is not None:
tgt = [dom for dom in self._domain]
tgt[space] = UnstructuredDomain(self._domain[space].shape)
else:
tgt = [UnstructuredDomain(dom.shape) for dom in self._domain]
self._target = DomainTuple.make(tgt)
self._capability = self.TIMES | self.ADJOINT_TIMES
def apply(self, x, mode):
self._check_input(x, mode)
return x.cast_domain(self._tgt(mode))
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)
self._capability = self.TIMES | self.ADJOINT_TIMES
@staticmethod
def _nullfield(dom):
if isinstance(dom, DomainTuple):
return Field(dom, 0)
else:
return MultiField.full(dom, 0)
def apply(self, x, mode):
self._check_input(x, mode)
return self._nullfield(self._tgt(mode))
class _PartialExtractor(LinearOperator):
def __init__(self, domain, target):
if not isinstance(domain, MultiDomain):
raise TypeError("MultiDomain expected")
if not isinstance(target, MultiDomain):
raise TypeError("MultiDomain expected")
self._domain = domain
self._target = target
for key in self._target.keys():
if not (self._domain[key] is not self._target[key]):
raise ValueError("domain mismatch")
self._capability = self.TIMES | self.ADJOINT_TIMES
def apply(self, x, mode):
self._check_input(x, mode)
if mode == self.TIMES:
return x.extract(self._target)
return MultiField.from_dict({key: x[key] for key in x.domain.keys()})
class MatrixProductOperator(EndomorphicOperator):
"""Endomorphic matrix multiplication with input field.
Parameters
----------
domain: DomainTuple
Domain of the operator.
matrix:
Matrix of shape (field.shape, field.shape)
space: int, optional
The index of the subdomain on which the operator should act
"""
def __init__(self, domain, matrix, space=None):
self._domain = DomainTuple.make(domain)
self._capability = self.TIMES | self.ADJOINT_TIMES
self._space = utilities.infer_space(self._domain, space)
self._mat = matrix
self._mat_tr = matrix.transpose()
def apply(self, x, mode):
self._check_input(x, mode)
res = x.to_global_data()
if mode == self.TIMES:
res = self._mat.dot(res)
if mode == self.ADJOINT_TIMES:
res = self._mat_tr.dot(res)
return Field.from_global_data(self._domain, res)
def __repr__(self):
return "MatrixProductOperator"