energy_and_model_tests.py 4.3 KB
Newer Older
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
# 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) 2013-2018 Max-Planck-Society
#
# NIFTy is being developed at the Max-Planck-Institut fuer Astrophysik
# and financially supported by the Studienstiftung des deutschen Volkes.

import numpy as np
Martin Reinecke's avatar
Martin Reinecke committed
20
from ..sugar import from_random
Martin Reinecke's avatar
tweak    
Martin Reinecke committed
21
22
from ..minimization.energy import Energy
from ..models.model import Model
23

Martin Reinecke's avatar
Martin Reinecke committed
24
25
__all__ = ["check_value_gradient_consistency",
           "check_value_gradient_curvature_consistency"]
26

Philipp Arras's avatar
Philipp Arras committed
27

28
29
30
31
32
33
34
def _get_acceptable_model(M):
    val = M.value
    if not np.isfinite(val.sum()):
        raise ValueError('Initial Model value must be finite')
    dir = from_random("normal", M.position.domain)
    dirder = M.gradient(dir)
    dir *= val/(dirder).norm()*1e-5
Philipp Arras's avatar
Philipp Arras committed
35
    # Find a step length that leads to a "reasonable" Model
36
37
38
39
40
41
42
43
44
45
46
47
    for i in range(50):
        try:
            M2 = M.at(M.position+dir)
            if np.isfinite(M2.value.sum()) and abs(M2.value.sum()) < 1e20:
                break
        except FloatingPointError:
            pass
        dir *= 0.5
    else:
        raise ValueError("could not find a reasonable initial step")
    return M2

48

Martin Reinecke's avatar
Martin Reinecke committed
49
def _get_acceptable_energy(E):
50
51
    val = E.value
    if not np.isfinite(val):
52
        raise ValueError('Initial Energy must be finite')
53
    dir = from_random("normal", E.position.domain)
54
55
    dirder = E.gradient.vdot(dir)
    dir *= np.abs(val)/np.abs(dirder)*1e-5
Philipp Arras's avatar
Philipp Arras committed
56
    # Find a step length that leads to a "reasonable" energy
Martin Reinecke's avatar
Martin Reinecke committed
57
58
59
60
61
62
63
64
65
66
67
68
69
    for i in range(50):
        try:
            E2 = E.at(E.position+dir)
            if np.isfinite(E2.value) and abs(E2.value) < 1e20:
                break
        except FloatingPointError:
            pass
        dir *= 0.5
    else:
        raise ValueError("could not find a reasonable initial step")
    return E2


Martin Reinecke's avatar
Martin Reinecke committed
70
def check_value_gradient_consistency(E, tol=1e-8, ntries=100):
71
    for _ in range(ntries):
72
73
74
75
        if isinstance(E, Energy):
            E2 = _get_acceptable_energy(E)
        else:
            E2 = _get_acceptable_model(E)
76
        val = E.value
Martin Reinecke's avatar
Martin Reinecke committed
77
        dir = E2.position - E.position
Martin Reinecke's avatar
tweak    
Martin Reinecke committed
78
        Enext = E2
Martin Reinecke's avatar
Martin Reinecke committed
79
        dirnorm = dir.norm()
80
        for i in range(50):
Martin Reinecke's avatar
Martin Reinecke committed
81
            Emid = E.at(E.position + 0.5*dir)
82
83
84
85
            if isinstance(E, Energy):
                dirder = Emid.gradient.vdot(dir)/dirnorm
            else:
                dirder = Emid.gradient(dir)/dirnorm
86
            numgrad = (E2.value-val)/dirnorm
87
            if isinstance(E, Model):
88
                xtol = tol * dirder.norm() / np.sqrt(dirder.size)
89
                if (abs(numgrad-dirder) < xtol).all():
90
91
92
                    break
            else:
                xtol = tol*Emid.gradient_norm
93
                if abs(numgrad-dirder) < xtol:
94
                    break
95
            dir *= 0.5
Martin Reinecke's avatar
Martin Reinecke committed
96
            dirnorm *= 0.5
Martin Reinecke's avatar
Martin Reinecke committed
97
            E2 = Emid
98
        else:
Martin Reinecke's avatar
Martin Reinecke committed
99
            raise ValueError("gradient and value seem inconsistent")
Martin Reinecke's avatar
tweak    
Martin Reinecke committed
100
        E = Enext
Martin Reinecke's avatar
Martin Reinecke committed
101
102


Martin Reinecke's avatar
Martin Reinecke committed
103
def check_value_gradient_curvature_consistency(E, tol=1e-8, ntries=100):
104
105
    if isinstance(E, Model):
        raise ValueError('Models have no curvature, thus it cannot be tested.')
Martin Reinecke's avatar
Martin Reinecke committed
106
107
    for _ in range(ntries):
        E2 = _get_acceptable_energy(E)
108
        val = E.value
Martin Reinecke's avatar
Martin Reinecke committed
109
        dir = E2.position - E.position
Martin Reinecke's avatar
tweak    
Martin Reinecke committed
110
        Enext = E2
Martin Reinecke's avatar
Martin Reinecke committed
111
        dirnorm = dir.norm()
112
        for i in range(50):
113
114
115
            Emid = E.at(E.position + 0.5*dir)
            dirder = Emid.gradient.vdot(dir)/dirnorm
            dgrad = Emid.curvature(dir)/dirnorm
Martin Reinecke's avatar
Martin Reinecke committed
116
117
118
            xtol = tol*Emid.gradient_norm
            if abs((E2.value-val)/dirnorm - dirder) < xtol and \
               (abs((E2.gradient-E.gradient)/dirnorm-dgrad) < xtol).all():
119
120
                break
            dir *= 0.5
Martin Reinecke's avatar
Martin Reinecke committed
121
            dirnorm *= 0.5
122
            E2 = Emid
123
        else:
Martin Reinecke's avatar
Martin Reinecke committed
124
            raise ValueError("gradient, value and curvature seem inconsistent")
Martin Reinecke's avatar
tweak    
Martin Reinecke committed
125
        E = Enext