Commit cf834a3e authored by Theo Steininger's avatar Theo Steininger

Added ProjectionOperator

parent e42a55b7
Pipeline #10182 passed with stages
in 16 minutes and 16 seconds
......@@ -35,4 +35,6 @@ from invertible_operator_mixin import InvertibleOperatorMixin
from propagator_operator import PropagatorOperator
from propagator_operator import PropagatorOperator
from composed_operator import ComposedOperator
# -*- coding: utf-8 -*-
from projection_operator import ProjectionOperator
# -*- coding: utf-8 -*-
import numpy as np
from nifty.field import Field
from nifty.operators.endomorphic_operator import EndomorphicOperator
class ProjectionOperator(EndomorphicOperator):
# ---Overwritten properties and methods---
def __init__(self, projection_field):
if not isinstance(projection_field, Field):
raise TypeError("The projection_field must be a NIFTy-Field"
"instance.")
self._projection_field = projection_field
self._unitary = None
def _times(self, x, spaces):
# if the domain matches directly
# -> multiply the fields directly
if x.domain == self.domain:
# here the actual multiplication takes place
dotted = (self._projection_field * x).sum()
return self._projection_field * dotted
# if the distribution_strategy of self is sub-slice compatible to
# the one of x, reshape the local data of self and apply it directly
active_axes = []
if spaces is None:
active_axes = range(len(x.shape))
else:
for space_index in spaces:
active_axes += x.domain_axes[space_index]
axes_local_distribution_strategy = \
x.val.get_axes_local_distribution_strategy(active_axes)
if axes_local_distribution_strategy == \
self._projection_field.distribution_strategy:
local_projection_vector = \
self._projection_field.val.get_local_data(copy=False)
else:
# create an array that is sub-slice compatible
self.logger.warn("The input field is not sub-slice compatible to "
"the distribution strategy of the operator. "
"Performing an probably expensive "
"redistribution.")
redistr_projection_val = self._projection_field.val.copy(
distribution_strategy=axes_local_distribution_strategy)
local_projection_vector = \
redistr_projection_val.get_local_data(copy=False)
local_x = x.val.get_local_data(copy=False)
l = len(local_projection_vector.shape)
sublist_projector = range(l)
sublist_x = np.arange(len(local_x.shape)) + l
for i in xrange(l):
a = active_axes[i]
sublist_x[a] = i
dotted = np.einsum(local_projection_vector, sublist_projector,
local_x, sublist_x)
# get those elements from sublist_x that haven't got contracted
sublist_dotted = sublist_x[sublist_x >= l]
remultiplied = np.einsum(local_projection_vector, sublist_projector,
dotted, sublist_dotted,
sublist_x)
result_field = x.copy_empty(dtype=remultiplied.dtype)
result_field.val.set_local_data(remultiplied, copy=False)
return result_field
def _inverse_times(self, x, spaces):
raise NotImplementedError("The ProjectionOperator is a singular "
"operator and therefore has no inverse.")
# ---Mandatory properties and methods---
@property
def domain(self):
return self._projection_field.domain
@property
def implemented(self):
return True
@property
def unitary(self):
if self._unitary is None:
self._unitary = (self._projection_field.val == 1).all()
return self._unitary
@property
def symmetric(self):
return True
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