chain_operator.py 4.63 KB
Newer Older
Martin Reinecke's avatar
Martin Reinecke committed
1
2
3
4
5
6
7
8
9
10
11
12
13
# 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/>.
#
14
# Copyright(C) 2013-2018 Max-Planck-Society
Martin Reinecke's avatar
Martin Reinecke committed
15
16
17
18
#
# NIFTy is being developed at the Max-Planck-Institut fuer Astrophysik
# and financially supported by the Studienstiftung des deutschen Volkes.

19
import numpy as np
Martin Reinecke's avatar
Martin Reinecke committed
20
21
22
23
from .linear_operator import LinearOperator


class ChainOperator(LinearOperator):
Martin Reinecke's avatar
Martin Reinecke committed
24
25
    """Class representing chains of operators."""

Martin Reinecke's avatar
Martin Reinecke committed
26
27
28
    def __init__(self, ops, _callingfrommake=False):
        if not _callingfrommake:
            raise NotImplementedError
Martin Reinecke's avatar
Martin Reinecke committed
29
        super(ChainOperator, self).__init__()
Martin Reinecke's avatar
Martin Reinecke committed
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
        self._ops = ops
        self._capability = self._all_ops
        for op in ops:
            self._capability &= op.capability

    @staticmethod
    def simplify(ops):
        from .scaling_operator import ScalingOperator
        from .diagonal_operator import DiagonalOperator
        # Step 1: verify domains
        for i in range(len(ops)-1):
            if ops[i+1].target != ops[i].domain:
                raise ValueError("domain mismatch")
        # Step 2: unpack ChainOperators
        opsnew = []
        for op in ops:
            if isinstance(op, ChainOperator):
                opsnew += op._ops
            else:
                opsnew.append(op)
        ops = opsnew
        # Step 3: collect ScalingOperators
        fct = 1.
        opsnew = []
        lastdom = ops[-1].domain
        for op in ops:
56
57
            if (isinstance(op, ScalingOperator) and
                    not np.issubdtype(type(op._factor), np.complexfloating)):
Martin Reinecke's avatar
Martin Reinecke committed
58
59
60
61
62
63
64
                fct *= op._factor
            else:
                opsnew.append(op)
        if fct != 1.:
            # try to absorb the factor into a DiagonalOperator
            for i in range(len(opsnew)):
                if isinstance(opsnew[i], DiagonalOperator):
Martin Reinecke's avatar
Martin Reinecke committed
65
                    opsnew[i] = opsnew[i]._scale(fct)
Martin Reinecke's avatar
Martin Reinecke committed
66
67
                    fct = 1.
                    break
Martin Reinecke's avatar
bug fix    
Martin Reinecke committed
68
        if fct != 1 or len(opsnew) == 0:
Martin Reinecke's avatar
Martin Reinecke committed
69
70
71
72
73
74
75
76
            # have to add the scaling operator at the end
            opsnew.append(ScalingOperator(fct, lastdom))
        ops = opsnew
        # Step 4: combine DiagonalOperators where possible
        opsnew = []
        for op in ops:
            if (len(opsnew) > 0 and
                    isinstance(opsnew[-1], DiagonalOperator) and
77
                    isinstance(op, DiagonalOperator)):
Martin Reinecke's avatar
Martin Reinecke committed
78
                opsnew[-1] = opsnew[-1]._combine_prod(op)
Martin Reinecke's avatar
Martin Reinecke committed
79
80
81
            else:
                opsnew.append(op)
        ops = opsnew
Martin Reinecke's avatar
Martin Reinecke committed
82
83
84
85
86
87
88
89
90
91
92
        # Step 5: combine BlockDiagonalOperators where possible
        from ..multi.block_diagonal_operator import BlockDiagonalOperator
        opsnew = []
        for op in ops:
            if (len(opsnew) > 0 and
                    isinstance(opsnew[-1], BlockDiagonalOperator) and
                    isinstance(op, BlockDiagonalOperator)):
                opsnew[-1] = opsnew[-1]._combine_chain(op)
            else:
                opsnew.append(op)
        ops = opsnew
Martin Reinecke's avatar
Martin Reinecke committed
93
94
95
96
97
        return ops

    @staticmethod
    def make(ops):
        ops = tuple(ops)
Martin Reinecke's avatar
bug fix    
Martin Reinecke committed
98
99
        if len(ops) == 0:
            raise ValueError("ops is empty")
Martin Reinecke's avatar
Martin Reinecke committed
100
101
102
103
        ops = ChainOperator.simplify(ops)
        if len(ops) == 1:
            return ops[0]
        return ChainOperator(ops, _callingfrommake=True)
Martin Reinecke's avatar
Martin Reinecke committed
104
105
106

    @property
    def domain(self):
Martin Reinecke's avatar
Martin Reinecke committed
107
        return self._ops[-1].domain
Martin Reinecke's avatar
Martin Reinecke committed
108
109
110

    @property
    def target(self):
Martin Reinecke's avatar
Martin Reinecke committed
111
        return self._ops[0].target
Martin Reinecke's avatar
Martin Reinecke committed
112

113
114
115
116
117
    def _flip_modes(self, trafo):
        ADJ = self.ADJOINT_BIT
        INV = self.INVERSE_BIT

        if trafo == 0:
Martin Reinecke's avatar
Martin Reinecke committed
118
            return self
119
120
        if trafo == ADJ or trafo == INV:
            return self.make([op._flip_modes(trafo)
Martin Reinecke's avatar
Martin Reinecke committed
121
                              for op in reversed(self._ops)])
122
123
124
        if trafo == ADJ | INV:
            return self.make([op._flip_modes(trafo) for op in self._ops])
        raise ValueError("invalid operator transformation")
Martin Reinecke's avatar
Martin Reinecke committed
125

Martin Reinecke's avatar
Martin Reinecke committed
126
127
    @property
    def capability(self):
Martin Reinecke's avatar
Martin Reinecke committed
128
        return self._capability
Martin Reinecke's avatar
Martin Reinecke committed
129
130
131

    def apply(self, x, mode):
        self._check_mode(mode)
Martin Reinecke's avatar
Martin Reinecke committed
132
133
134
135
        t_ops = self._ops if mode & self._backwards else reversed(self._ops)
        for op in t_ops:
            x = op.apply(x, mode)
        return x