sum_operator.py 6.29 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 19
#
# NIFTy is being developed at the Max-Planck-Institut fuer Astrophysik
# and financially supported by the Studienstiftung des deutschen Volkes.

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


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

Martin Reinecke's avatar
Martin Reinecke committed
26
    def __init__(self, ops, neg, dom, tgt, _callingfrommake=False):
27 28
        if not _callingfrommake:
            raise NotImplementedError
Martin Reinecke's avatar
Martin Reinecke committed
29
        super(SumOperator, self).__init__()
30 31
        self._ops = ops
        self._neg = neg
Martin Reinecke's avatar
Martin Reinecke committed
32 33
        self._domain = dom
        self._target = tgt
34 35 36 37 38 39 40 41 42
        self._capability = self.TIMES | self.ADJOINT_TIMES
        for op in ops:
            self._capability &= op.capability

    @staticmethod
    def simplify(ops, neg):
        from .scaling_operator import ScalingOperator
        from .diagonal_operator import DiagonalOperator
        # Step 1: verify domains
Martin Reinecke's avatar
Martin Reinecke committed
43 44
        dom = ops[0].domain
        tgt = ops[0].target
45
        for op in ops[1:]:
Martin Reinecke's avatar
Martin Reinecke committed
46 47 48
            dom = dom.unitedWith(op.domain)
            tgt = tgt.unitedWith(op.target)

49 50 51
        # Step 2: unpack SumOperators
        opsnew = []
        negnew = []
52
        for op, ng in zip(ops, neg):
53 54 55
            if isinstance(op, SumOperator):
                opsnew += op._ops
                if ng:
Martin Reinecke's avatar
fixes  
Martin Reinecke committed
56
                    negnew += [not n for n in op._neg]
57
                else:
Martin Reinecke's avatar
fixes  
Martin Reinecke committed
58
                    negnew += list(op._neg)
59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79
            else:
                opsnew.append(op)
                negnew.append(ng)
        ops = opsnew
        neg = negnew
        # Step 3: collect ScalingOperators
        sum = 0.
        opsnew = []
        negnew = []
        lastdom = ops[-1].domain
        for op, ng in zip(ops, neg):
            if isinstance(op, ScalingOperator):
                sum += op._factor * (-1 if ng else 1)
            else:
                opsnew.append(op)
                negnew.append(ng)
        if sum != 0.:
            # try to absorb the factor into a DiagonalOperator
            for i in range(len(opsnew)):
                if isinstance(opsnew[i], DiagonalOperator):
                    sum *= (-1 if negnew[i] else 1)
Martin Reinecke's avatar
Martin Reinecke committed
80
                    opsnew[i] = opsnew[i]._add(sum)
81 82 83 84 85
                    sum = 0.
                    break
        if sum != 0:
            # have to add the scaling operator at the end
            opsnew.append(ScalingOperator(sum, lastdom))
86
            negnew.append(False)
87 88 89
        ops = opsnew
        neg = negnew
        # Step 4: combine DiagonalOperators where possible
90 91 92 93 94 95
        processed = [False] * len(ops)
        opsnew = []
        negnew = []
        for i in range(len(ops)):
            if not processed[i]:
                if isinstance(ops[i], DiagonalOperator):
Martin Reinecke's avatar
Martin Reinecke committed
96 97
                    op = ops[i]
                    opneg = neg[i]
98
                    for j in range(i+1, len(ops)):
Martin Reinecke's avatar
Martin Reinecke committed
99 100 101
                        if isinstance(ops[j], DiagonalOperator):
                            op = op._combine_sum(ops[j], opneg, neg[j])
                            opneg = False
102
                            processed[j] = True
Martin Reinecke's avatar
Martin Reinecke committed
103 104
                    opsnew.append(op)
                    negnew.append(opneg)
105 106 107 108 109
                else:
                    opsnew.append(ops[i])
                    negnew.append(neg[i])
        ops = opsnew
        neg = negnew
Martin Reinecke's avatar
Martin Reinecke committed
110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131
        # Step 5: combine BlockDiagonalOperators where possible
        from ..multi.block_diagonal_operator import BlockDiagonalOperator
        processed = [False] * len(ops)
        opsnew = []
        negnew = []
        for i in range(len(ops)):
            if not processed[i]:
                if isinstance(ops[i], BlockDiagonalOperator):
                    op = ops[i]
                    opneg = neg[i]
                    for j in range(i+1, len(ops)):
                        if isinstance(ops[j], BlockDiagonalOperator):
                            op = op._combine_sum(ops[j], opneg, neg[j])
                            opneg = False
                            processed[j] = True
                    opsnew.append(op)
                    negnew.append(opneg)
                else:
                    opsnew.append(ops[i])
                    negnew.append(neg[i])
        ops = opsnew
        neg = negnew
Martin Reinecke's avatar
Martin Reinecke committed
132
        return ops, neg, dom, tgt
133 134 135 136 137

    @staticmethod
    def make(ops, neg):
        ops = tuple(ops)
        neg = tuple(neg)
Martin Reinecke's avatar
bug fix  
Martin Reinecke committed
138 139
        if len(ops) == 0:
            raise ValueError("ops is empty")
140
        if len(ops) != len(neg):
141
            raise ValueError("length mismatch between ops and neg")
Martin Reinecke's avatar
Martin Reinecke committed
142
        ops, neg, dom, tgt = SumOperator.simplify(ops, neg)
143 144
        if len(ops) == 1 and not neg[0]:
            return ops[0]
Martin Reinecke's avatar
Martin Reinecke committed
145
        return SumOperator(ops, neg, dom, tgt, _callingfrommake=True)
Martin Reinecke's avatar
Martin Reinecke committed
146 147 148

    @property
    def domain(self):
Martin Reinecke's avatar
Martin Reinecke committed
149
        return self._domain
Martin Reinecke's avatar
Martin Reinecke committed
150 151 152

    @property
    def target(self):
Martin Reinecke's avatar
Martin Reinecke committed
153
        return self._target
Martin Reinecke's avatar
Martin Reinecke committed
154

Martin Reinecke's avatar
Martin Reinecke committed
155 156 157 158
    @property
    def adjoint(self):
        return self.make([op.adjoint for op in self._ops], self._neg)

Martin Reinecke's avatar
Martin Reinecke committed
159 160
    @property
    def capability(self):
Martin Reinecke's avatar
Martin Reinecke committed
161
        return self._capability
Martin Reinecke's avatar
Martin Reinecke committed
162 163 164

    def apply(self, x, mode):
        self._check_mode(mode)
Martin Reinecke's avatar
Martin Reinecke committed
165 166 167 168 169 170 171 172 173
        for i, op in enumerate(self._ops):
            if i == 0:
                res = -op.apply(x, mode) if self._neg[i] else op.apply(x, mode)
            else:
                if self._neg[i]:
                    res -= op.apply(x, mode)
                else:
                    res += op.apply(x, mode)
        return res
Martin Reinecke's avatar
Martin Reinecke committed
174

175 176
    def draw_sample(self, from_inverse=False, dtype=np.float64):
        if from_inverse:
177 178
            raise NotImplementedError(
                "cannot draw from inverse of this operator")
179
        res = self._ops[0].draw_sample(from_inverse, dtype)
Martin Reinecke's avatar
Martin Reinecke committed
180
        for op in self._ops[1:]:
181
            res += op.draw_sample(from_inverse, dtype)
Martin Reinecke's avatar
Martin Reinecke committed
182
        return res