diagonal_operator.py 5.37 KB
Newer Older
1
2
3
4
5
6
7
8
9
10
11
12
# 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/>.
Theo Steininger's avatar
Theo Steininger committed
13
14
15
16
17
#
# Copyright(C) 2013-2017 Max-Planck-Society
#
# NIFTy is being developed at the Max-Planck-Institut fuer Astrophysik
# and financially supported by the Studienstiftung des deutschen Volkes.
18

Martin Reinecke's avatar
Martin Reinecke committed
19
20
from __future__ import division
from builtins import range
21
22
import numpy as np

Martin Reinecke's avatar
Martin Reinecke committed
23
from ...field import Field
Martin Reinecke's avatar
Martin Reinecke committed
24
from ...domain_tuple import DomainTuple
Martin Reinecke's avatar
Martin Reinecke committed
25
from ..endomorphic_operator import EndomorphicOperator
26
from ...nifty_utilities import cast_iseq_to_tuple
27
28

class DiagonalOperator(EndomorphicOperator):
Theo Steininger's avatar
Theo Steininger committed
29
30
31
32
33
    """ NIFTY class for diagonal operators.

    The NIFTY DiagonalOperator class is a subclass derived from the
    EndomorphicOperator. It multiplies an input field pixel-wise with its
    diagonal.
34

35
36
37

    Parameters
    ----------
Martin Reinecke's avatar
Martin Reinecke committed
38
    diagonal : Field
39
        The diagonal entries of the operator.
40
41
42
43
44
45
    domain : tuple of DomainObjects, i.e. Spaces and FieldTypes
        The domain on which the Operator's input Field lives.
        If None, use the domain of "diagonal".
    spaces : tuple of int
        The elements of "domain" on which the operator acts.
        If None, it acts on all elements.
46
47
48

    Attributes
    ----------
49
50
51
52
53
54
55
56
57
    domain : tuple of DomainObjects, i.e. Spaces and FieldTypes
        The domain on which the Operator's input Field lives.
    target : tuple of DomainObjects, i.e. Spaces and FieldTypes
        The domain in which the outcome of the operator lives. As the Operator
        is endomorphic this is the same as its domain.
    unitary : boolean
        Indicates whether the Operator is unitary or not.
    self_adjoint : boolean
        Indicates whether the operator is self_adjoint or not.
58
59
60
61
62
63
64

    See Also
    --------
    EndomorphicOperator

    """

65
66
    # ---Overwritten properties and methods---

67
    def __init__(self, diagonal, domain=None, spaces=None):
68
        super(DiagonalOperator, self).__init__()
69

Martin Reinecke's avatar
Martin Reinecke committed
70
71
        if not isinstance(diagonal, Field):
            raise TypeError("Field object required")
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
        if domain is None:
            self._domain = diagonal.domain
        else:
            self._domain = DomainTuple.make(domain)
        if spaces is None:
            self._spaces = None
            if diagonal.domain != self._domain:
                raise ValueError("domain mismatch")
        else:
            self._spaces = cast_iseq_to_tuple(spaces)
            nspc = len(self._spaces)
            if nspc != len(diagonal.domain.domains):
                raise ValueError("spaces and domain must have the same length")
            if nspc > len(self._domain.domains):
                raise ValueError("too many spaces")
            if nspc > len(set(self._spaces)):
                raise ValueError("non-unique space indices")
            # if nspc==len(self.diagonal.domain.domains, we could do some optimization
            for i, j  in enumerate(self._spaces):
                if diagonal.domain[i] != self._domain[j]:
                    raise ValueError("domain mismatch")

94
        self._diagonal = diagonal.weight(1)
95
96
        self._self_adjoint = None
        self._unitary = None
97

98
99
    def _times(self, x):
        return self._times_helper(x, lambda z: z.__mul__)
100

101
102
    def _adjoint_times(self, x):
        return self._times_helper(x, lambda z: z.conjugate().__mul__)
103

104
105
    def _inverse_times(self, x):
        return self._times_helper(x, lambda z: z.__rtruediv__)
106

107
108
    def _adjoint_inverse_times(self, x):
        return self._times_helper(x, lambda z: z.conjugate().__rtruediv__)
109

110
    def diagonal(self):
111
112
113
114
115
116
117
118
        """ Returns the diagonal of the Operator.

        Returns
        -------
        out : Field
            The diagonal of the Operator.

        """
119
        return self._diagonal.weight(-1)
120

121
122
    # ---Mandatory properties and methods---

123
124
    @property
    def domain(self):
125
        return self._domain
126

127
    @property
Martin Reinecke's avatar
Martin Reinecke committed
128
129
    def self_adjoint(self):
        if self._self_adjoint is None:
Martin Reinecke's avatar
Martin Reinecke committed
130
131
132
133
            if not issubclass(self._diagonal.dtype.type, np.complexfloating):
                self._self_adjoint = True
            else:
                self._self_adjoint = (self._diagonal.val.imag == 0).all()
Martin Reinecke's avatar
Martin Reinecke committed
134
        return self._self_adjoint
135
136
137

    @property
    def unitary(self):
138
        if self._unitary is None:
Martin Reinecke's avatar
Martin Reinecke committed
139
            self._unitary = (abs(self._diagonal.val) == 1.).all()
140
141
142
143
        return self._unitary

    # ---Added properties and methods---

144
145
    def _times_helper(self, x, operation):
        if self._spaces is None:
Martin Reinecke's avatar
tweaks    
Martin Reinecke committed
146
            return operation(self._diagonal)(x)
147

148
149
150
        active_axes = []
        for space_index in self._spaces:
            active_axes += x.domain.axes[space_index]
151

Martin Reinecke's avatar
Martin Reinecke committed
152
        reshaper = [x.shape[i] if i in active_axes else 1
Martin Reinecke's avatar
Martin Reinecke committed
153
                    for i in range(len(x.shape))]
Martin Reinecke's avatar
tweaks    
Martin Reinecke committed
154
        reshaped_local_diagonal = np.reshape(self._diagonal.val, reshaper)
155
156

        # here the actual multiplication takes place
157
        return Field(x.domain, val=operation(reshaped_local_diagonal)(x.val))