File: test_units.py

package info (click to toggle)
mdanalysis 2.10.0-1
  • links: PTS, VCS
  • area: main
  • in suites: forky, sid
  • size: 116,696 kB
  • sloc: python: 92,135; ansic: 8,156; makefile: 215; sh: 138
file content (188 lines) | stat: -rw-r--r-- 6,483 bytes parent folder | download
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
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
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
# -*- Mode: python; tab-width: 4; indent-tabs-mode:nil; coding:utf-8 -*-
# vim: tabstop=4 expandtab shiftwidth=4 softtabstop=4 fileencoding=utf-8
#
# MDAnalysis --- https://www.mdanalysis.org
# Copyright (c) 2006-2017 The MDAnalysis Development Team and contributors
# (see the file AUTHORS for the full list of names)
#
# Released under the Lesser GNU Public Licence, v2.1 or any higher version
#
# Please cite your use of MDAnalysis in published work:
#
# R. J. Gowers, M. Linke, J. Barnoud, T. J. E. Reddy, M. N. Melo, S. L. Seyler,
# D. L. Dotson, J. Domanski, S. Buchoux, I. M. Kenney, and O. Beckstein.
# MDAnalysis: A Python package for the rapid analysis of molecular dynamics
# simulations. In S. Benthall and S. Rostrup editors, Proceedings of the 15th
# Python in Science Conference, pages 102-109, Austin, TX, 2016. SciPy.
# doi: 10.25080/majora-629e541a-00e
#
# N. Michaud-Agrawal, E. J. Denning, T. B. Woolf, and O. Beckstein.
# MDAnalysis: A Toolkit for the Analysis of Molecular Dynamics Simulations.
# J. Comput. Chem. 32 (2011), 2319--2327, doi:10.1002/jcc.21787
#
import pytest

import numpy as np
from numpy.testing import assert_equal, assert_almost_equal

from MDAnalysis import units


class TestUnitEncoding(object):
    def test_unicode(self):
        try:
            assert_equal(units.lengthUnit_factor["\u212b"], 1.0)
        except KeyError:
            raise AssertionError("Unicode symbol for Angtrom not supported")

    def test_unicode_encoding_with_symbol(self):
        try:
            assert_equal(units.lengthUnit_factor["Å"], 1.0)
        except KeyError:
            raise AssertionError(
                "UTF-8-encoded symbol for Angtrom not supported"
            )


class TestConstants(object):
    # CODATA 2010 (NIST): http://physics.nist.gov/cuu/Constants/
    # (accessed 2015-02-15)
    # Add a reference value to this dict for every entry in
    # units.constants
    constants_reference = (
        ("N_Avogadro", 6.02214129e23),  # mol**-1
        ("elementary_charge", 1.602176565e-19),  # As
        ("calorie", 4.184),  # J
        ("Boltzmann_constant", 8.314462159e-3),  # KJ (mol K)**-1
        ("Boltzman_constant", 8.314462159e-3),  # remove in 2.8.0
        ("electric_constant", 5.526350e-3),  # As (Angstroms Volts)**-1
    )

    @pytest.mark.parametrize("name, value", constants_reference)
    def test_constant(self, name, value):
        assert_almost_equal(units.constants[name], value)

    def test_boltzmann_typo_deprecation(self):
        wmsg = (
            "Please use 'Boltzmann_constant' henceforth. The key "
            "'Boltzman_constant' was a typo and will be removed "
            "in MDAnalysis 2.8.0."
        )
        with pytest.warns(DeprecationWarning, match=wmsg):
            units.constants["Boltzman_constant"]


class TestConversion(object):
    @staticmethod
    def _assert_almost_equal_convert(value, u1, u2, ref):
        val = units.convert(value, u1, u2)
        assert_almost_equal(
            val, ref, err_msg="Conversion {0} --> {1} failed".format(u1, u2)
        )

    nm = 12.34567
    A = nm * 10.0

    @pytest.mark.parametrize(
        "quantity, unit1, unit2, ref",
        (
            (nm, "nm", "A", A),
            (A, "Angstrom", "nm", nm),
            (A, "\u212b", "nm", nm),
        ),
    )
    def test_length(self, quantity, unit1, unit2, ref):
        self._assert_almost_equal_convert(quantity, unit1, unit2, ref)

    @pytest.mark.parametrize(
        "quantity, unit1, unit2, ref",
        (
            (1, "ps", "AKMA", 20.45482949774598),
            (1, "AKMA", "ps", 0.04888821),
            (1, "ps", "ms", 1e-9),
            (1, "ms", "ps", 1e9),
            (1, "ps", "us", 1e-6),
            (1, "us", "ps", 1e6),
            (1, "\u03BCs", "ps", 1e6),
            (1, "fs", "ns", 1e-6),
        ),
    )
    def test_time(self, quantity, unit1, unit2, ref):
        self._assert_almost_equal_convert(quantity, unit1, unit2, ref)

    @pytest.mark.parametrize(
        "quantity, unit1, unit2, ref",
        (
            (1, "kcal/mol", "kJ/mol", 4.184),
            (1, "kcal/mol", "eV", 0.0433641),
        ),
    )
    def test_energy(self, quantity, unit1, unit2, ref):
        self._assert_almost_equal_convert(quantity, unit1, unit2, ref)

    @pytest.mark.parametrize(
        "quantity, unit1, unit2, ref",
        (
            (1, "kJ/(mol*A)", "J/m", 1.66053892103219e-11),
            (2.5, "kJ/(mol*nm)", "kJ/(mol*A)", 0.25),
            (1, "kcal/(mol*Angstrom)", "kJ/(mol*Angstrom)", 4.184),
        ),
    )
    def test_force(self, quantity, unit1, unit2, ref):
        self._assert_almost_equal_convert(quantity, unit1, unit2, ref)

    @pytest.mark.parametrize(
        "quantity, unit1, unit2, ref",
        (
            (1, "A/ps", "m/s", 1e-10 / 1e-12),
            (1, "A/ps", "nm/ps", 0.1),
            (1, "A/ps", "pm/ps", 1e2),
            (1, "A/ms", "A/ps", 1e-9),
            (1, "A/us", "A/ps", 1e-6),
            (1, "A/\u03BCs", "A/ps", 1e-6),
            (1, "\u212b/\u03BCs", "A/ps", 1e-6),
            (1, "A/fs", "A/ps", 1e3),
            (1, "A/ps", "A/fs", 1e-3),
            (1, "A/ns", "A/ms", 1e6),
            (1, "\u212b/ns", "A/ms", 1e6),
            (1, "A/ps", "A/ps", 1.0),
            (1, "nm/ns", "pm/ps", 1.0),
            (1, "m/s", "A/fs", 1e-5),
            (1, "A/AKMA", "A/ps", 1 / 4.888821e-2),
        ),
    )
    def test_speed(self, quantity, unit1, unit2, ref):
        self._assert_almost_equal_convert(quantity, unit1, unit2, ref)

    @pytest.mark.parametrize(
        "quantity, unit1, unit2", ((nm, "Stone", "nm"), (nm, "nm", "Stone"))
    )
    def test_unit_unknown(self, quantity, unit1, unit2):
        with pytest.raises(ValueError):
            units.convert(quantity, unit1, unit2)

    def test_unit_unconvertable(self):
        nm = 12.34567
        A = nm * 10.0
        with pytest.raises(ValueError):
            units.convert(A, "A", "ps")


class TestBaseUnits:
    @staticmethod
    @pytest.fixture
    def ref():
        # This is a copy of the dictionary we expect.
        # We want to know if base units are added or altered.
        ref = {
            "length": "A",
            "time": "ps",
            "energy": "kJ/mol",
            "charge": "e",
            "force": "kJ/(mol*A)",
            "speed": "A/ps",
        }
        return ref

    def test_MDANALYSIS_BASE_UNITS_correct(self, ref):
        assert ref == units.MDANALYSIS_BASE_UNITS