File: test_event.py

package info (click to toggle)
python-mne 0.17%2Bdfsg-1
  • links: PTS, VCS
  • area: main
  • in suites: buster
  • size: 95,104 kB
  • sloc: python: 110,639; makefile: 222; sh: 15
file content (534 lines) | stat: -rw-r--r-- 21,785 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
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
import os.path as op
import os

import numpy as np
from numpy.testing import (assert_array_almost_equal, assert_array_equal,
                           assert_equal, assert_allclose)
import pytest

from mne import (read_events, write_events, make_fixed_length_events,
                 find_events, pick_events, find_stim_steps, pick_channels,
                 read_evokeds, Epochs, create_info, compute_raw_covariance)
from mne.io import read_raw_fif, RawArray
from mne.utils import _TempDir, run_tests_if_main
from mne.event import define_target_events, merge_events, AcqParserFIF
from mne.datasets import testing

base_dir = op.join(op.dirname(__file__), '..', 'io', 'tests', 'data')
fname = op.join(base_dir, 'test-eve.fif')
fname_gz = op.join(base_dir, 'test-eve.fif.gz')
fname_1 = op.join(base_dir, 'test-1-eve.fif')
fname_txt = op.join(base_dir, 'test-eve.eve')
fname_txt_1 = op.join(base_dir, 'test-eve-1.eve')

# for testing Elekta averager
elekta_base_dir = op.join(testing.data_path(download=False), 'misc')
fname_raw_elekta = op.join(elekta_base_dir, 'test_elekta_3ch_raw.fif')
fname_ave_elekta = op.join(elekta_base_dir, 'test_elekta-ave.fif')

# using mne_process_raw --raw test_raw.fif --eventsout test-mpr-eve.eve:
fname_txt_mpr = op.join(base_dir, 'test-mpr-eve.eve')
fname_old_txt = op.join(base_dir, 'test-eve-old-style.eve')
raw_fname = op.join(base_dir, 'test_raw.fif')


def test_fix_stim():
    """Test fixing stim STI016 for Neuromag."""
    raw = read_raw_fif(raw_fname, preload=True)
    # 32768 (016) + 3 (002+001) bits gets incorrectly coded during acquisition
    raw._data[raw.ch_names.index('STI 014'), :3] = [0, -32765, 0]
    with pytest.warns(RuntimeWarning, match='STI016'):
        events = find_events(raw, 'STI 014')
    assert_array_equal(events[0], [raw.first_samp + 1, 0, 32765])
    events = find_events(raw, 'STI 014', uint_cast=True)
    assert_array_equal(events[0], [raw.first_samp + 1, 0, 32771])


def test_add_events():
    """Test adding events to a Raw file."""
    # need preload
    raw = read_raw_fif(raw_fname)
    events = np.array([[raw.first_samp, 0, 1]])
    pytest.raises(RuntimeError, raw.add_events, events, 'STI 014')
    raw = read_raw_fif(raw_fname, preload=True)
    orig_events = find_events(raw, 'STI 014')
    # add some events
    events = np.array([raw.first_samp, 0, 1])
    pytest.raises(ValueError, raw.add_events, events, 'STI 014')  # bad shape
    events[0] = raw.first_samp + raw.n_times + 1
    events = events[np.newaxis, :]
    pytest.raises(ValueError, raw.add_events, events, 'STI 014')  # bad time
    events[0, 0] = raw.first_samp - 1
    pytest.raises(ValueError, raw.add_events, events, 'STI 014')  # bad time
    events[0, 0] = raw.first_samp + 1  # can't actually be first_samp
    pytest.raises(ValueError, raw.add_events, events, 'STI FOO')
    raw.add_events(events, 'STI 014')
    new_events = find_events(raw, 'STI 014')
    assert_array_equal(new_events, np.concatenate((events, orig_events)))
    raw.add_events(events, 'STI 014', replace=True)
    new_events = find_events(raw, 'STI 014')
    assert_array_equal(new_events, events)


def test_merge_events():
    """Test event merging."""
    events_orig = [[1, 0, 1], [3, 0, 2], [10, 0, 3], [20, 0, 4]]

    events_replacement = \
        [[1, 0, 12],
         [3, 0, 12],
         [10, 0, 34],
         [20, 0, 34]]

    events_no_replacement = \
        [[1, 0, 1],
         [1, 0, 12],
         [1, 0, 1234],
         [3, 0, 2],
         [3, 0, 12],
         [3, 0, 1234],
         [10, 0, 3],
         [10, 0, 34],
         [10, 0, 1234],
         [20, 0, 4],
         [20, 0, 34],
         [20, 0, 1234]]

    for replace_events, events_good in [(True, events_replacement),
                                        (False, events_no_replacement)]:
        events = merge_events(events_orig, [1, 2], 12, replace_events)
        events = merge_events(events, [3, 4], 34, replace_events)
        events = merge_events(events, [1, 2, 3, 4], 1234, replace_events)
        assert_array_equal(events, events_good)


def test_io_events():
    """Test IO for events."""
    tempdir = _TempDir()
    # Test binary fif IO
    events = read_events(fname)  # Use as the gold standard
    write_events(op.join(tempdir, 'events-eve.fif'), events)
    events2 = read_events(op.join(tempdir, 'events-eve.fif'))
    assert_array_almost_equal(events, events2)

    # Test binary fif.gz IO
    events2 = read_events(fname_gz)  # Use as the gold standard
    assert_array_almost_equal(events, events2)
    write_events(op.join(tempdir, 'events-eve.fif.gz'), events2)
    events2 = read_events(op.join(tempdir, 'events-eve.fif.gz'))
    assert_array_almost_equal(events, events2)

    # Test new format text file IO
    write_events(op.join(tempdir, 'events.eve'), events)
    events2 = read_events(op.join(tempdir, 'events.eve'))
    assert_array_almost_equal(events, events2)
    with pytest.warns(RuntimeWarning, match='first row of'):
        events2 = read_events(fname_txt_mpr, mask=0, mask_type='not_and')
    assert_array_almost_equal(events, events2)

    # Test old format text file IO
    events2 = read_events(fname_old_txt)
    assert_array_almost_equal(events, events2)
    write_events(op.join(tempdir, 'events.eve'), events)
    events2 = read_events(op.join(tempdir, 'events.eve'))
    assert_array_almost_equal(events, events2)

    # Test event selection
    a = read_events(op.join(tempdir, 'events-eve.fif'), include=1)
    b = read_events(op.join(tempdir, 'events-eve.fif'), include=[1])
    c = read_events(op.join(tempdir, 'events-eve.fif'),
                    exclude=[2, 3, 4, 5, 32])
    d = read_events(op.join(tempdir, 'events-eve.fif'), include=1,
                    exclude=[2, 3])
    assert_array_equal(a, b)
    assert_array_equal(a, c)
    assert_array_equal(a, d)

    # test reading file with mask=None
    events2 = events.copy()
    events2[:, -1] = range(events2.shape[0])
    write_events(op.join(tempdir, 'events-eve.fif'), events2)
    events3 = read_events(op.join(tempdir, 'events-eve.fif'), mask=None)
    assert_array_almost_equal(events2, events3)

    # Test binary file IO for 1 event
    events = read_events(fname_1)  # Use as the new gold standard
    write_events(op.join(tempdir, 'events-eve.fif'), events)
    events2 = read_events(op.join(tempdir, 'events-eve.fif'))
    assert_array_almost_equal(events, events2)

    # Test text file IO for 1 event
    write_events(op.join(tempdir, 'events.eve'), events)
    events2 = read_events(op.join(tempdir, 'events.eve'))
    assert_array_almost_equal(events, events2)

    # test warnings on bad filenames
    fname2 = op.join(tempdir, 'test-bad-name.fif')
    with pytest.warns(RuntimeWarning, match='-eve.fif'):
        write_events(fname2, events)
    with pytest.warns(RuntimeWarning, match='-eve.fif'):
        read_events(fname2)


def test_find_events():
    """Test find events in raw file."""
    events = read_events(fname)
    raw = read_raw_fif(raw_fname, preload=True)
    # let's test the defaulting behavior while we're at it
    extra_ends = ['', '_1']
    orig_envs = [os.getenv('MNE_STIM_CHANNEL%s' % s) for s in extra_ends]
    os.environ['MNE_STIM_CHANNEL'] = 'STI 014'
    if 'MNE_STIM_CHANNEL_1' in os.environ:
        del os.environ['MNE_STIM_CHANNEL_1']
    events2 = find_events(raw)
    assert_array_almost_equal(events, events2)
    # now test with mask
    events11 = find_events(raw, mask=3, mask_type='not_and')
    with pytest.warns(RuntimeWarning, match='events masked'):
        events22 = read_events(fname, mask=3, mask_type='not_and')
    assert_array_equal(events11, events22)

    # Reset some data for ease of comparison
    raw._first_samps[0] = 0
    raw.info['sfreq'] = 1000
    raw._update_times()

    stim_channel = 'STI 014'
    stim_channel_idx = pick_channels(raw.info['ch_names'],
                                     include=[stim_channel])

    # test digital masking
    raw._data[stim_channel_idx, :5] = np.arange(5)
    raw._data[stim_channel_idx, 5:] = 0
    # 1 == '0b1', 2 == '0b10', 3 == '0b11', 4 == '0b100'

    pytest.raises(TypeError, find_events, raw, mask="0", mask_type='and')
    pytest.raises(ValueError, find_events, raw, mask=0, mask_type='blah')
    # testing mask_type. default = 'not_and'
    assert_array_equal(find_events(raw, shortest_event=1, mask=1,
                                   mask_type='not_and'),
                       [[2, 0, 2], [4, 2, 4]])
    assert_array_equal(find_events(raw, shortest_event=1, mask=2,
                                   mask_type='not_and'),
                       [[1, 0, 1], [3, 0, 1], [4, 1, 4]])
    assert_array_equal(find_events(raw, shortest_event=1, mask=3,
                                   mask_type='not_and'),
                       [[4, 0, 4]])
    assert_array_equal(find_events(raw, shortest_event=1, mask=4,
                                   mask_type='not_and'),
                       [[1, 0, 1], [2, 1, 2], [3, 2, 3]])
    # testing with mask_type = 'and'
    assert_array_equal(find_events(raw, shortest_event=1, mask=1,
                       mask_type='and'),
                       [[1, 0, 1], [3, 0, 1]])
    assert_array_equal(find_events(raw, shortest_event=1, mask=2,
                       mask_type='and'),
                       [[2, 0, 2]])
    assert_array_equal(find_events(raw, shortest_event=1, mask=3,
                       mask_type='and'),
                       [[1, 0, 1], [2, 1, 2], [3, 2, 3]])
    assert_array_equal(find_events(raw, shortest_event=1, mask=4,
                       mask_type='and'),
                       [[4, 0, 4]])

    # test empty events channel
    raw._data[stim_channel_idx, :] = 0
    assert_array_equal(find_events(raw), np.empty((0, 3), dtype='int32'))

    raw._data[stim_channel_idx, :4] = 1
    assert_array_equal(find_events(raw), np.empty((0, 3), dtype='int32'))

    raw._data[stim_channel_idx, -1:] = 9
    assert_array_equal(find_events(raw), [[14399, 0, 9]])

    # Test that we can handle consecutive events with no gap
    raw._data[stim_channel_idx, 10:20] = 5
    raw._data[stim_channel_idx, 20:30] = 6
    raw._data[stim_channel_idx, 30:32] = 5
    raw._data[stim_channel_idx, 40] = 6

    assert_array_equal(find_events(raw, consecutive=False),
                       [[10, 0, 5],
                        [40, 0, 6],
                        [14399, 0, 9]])
    assert_array_equal(find_events(raw, consecutive=True),
                       [[10, 0, 5],
                        [20, 5, 6],
                        [30, 6, 5],
                        [40, 0, 6],
                        [14399, 0, 9]])
    assert_array_equal(find_events(raw),
                       [[10, 0, 5],
                        [20, 5, 6],
                        [40, 0, 6],
                        [14399, 0, 9]])
    assert_array_equal(find_events(raw, output='offset', consecutive=False),
                       [[31, 0, 5],
                        [40, 0, 6],
                        [14399, 0, 9]])
    assert_array_equal(find_events(raw, output='offset', consecutive=True),
                       [[19, 6, 5],
                        [29, 5, 6],
                        [31, 0, 5],
                        [40, 0, 6],
                        [14399, 0, 9]])
    pytest.raises(ValueError, find_events, raw, output='step',
                  consecutive=True)
    assert_array_equal(find_events(raw, output='step', consecutive=True,
                                   shortest_event=1),
                       [[10, 0, 5],
                        [20, 5, 6],
                        [30, 6, 5],
                        [32, 5, 0],
                        [40, 0, 6],
                        [41, 6, 0],
                        [14399, 0, 9],
                        [14400, 9, 0]])
    assert_array_equal(find_events(raw, output='offset'),
                       [[19, 6, 5],
                        [31, 0, 6],
                        [40, 0, 6],
                        [14399, 0, 9]])
    assert_array_equal(find_events(raw, consecutive=False, min_duration=0.002),
                       [[10, 0, 5]])
    assert_array_equal(find_events(raw, consecutive=True, min_duration=0.002),
                       [[10, 0, 5],
                        [20, 5, 6],
                        [30, 6, 5]])
    assert_array_equal(find_events(raw, output='offset', consecutive=False,
                                   min_duration=0.002),
                       [[31, 0, 5]])
    assert_array_equal(find_events(raw, output='offset', consecutive=True,
                                   min_duration=0.002),
                       [[19, 6, 5],
                        [29, 5, 6],
                        [31, 0, 5]])
    assert_array_equal(find_events(raw, consecutive=True, min_duration=0.003),
                       [[10, 0, 5],
                        [20, 5, 6]])

    # test find_stim_steps merge parameter
    raw._data[stim_channel_idx, :] = 0
    raw._data[stim_channel_idx, 0] = 1
    raw._data[stim_channel_idx, 10] = 4
    raw._data[stim_channel_idx, 11:20] = 5
    assert_array_equal(find_stim_steps(raw, pad_start=0, merge=0,
                                       stim_channel=stim_channel),
                       [[0, 0, 1],
                        [1, 1, 0],
                        [10, 0, 4],
                        [11, 4, 5],
                        [20, 5, 0]])
    assert_array_equal(find_stim_steps(raw, merge=-1,
                                       stim_channel=stim_channel),
                       [[1, 1, 0],
                        [10, 0, 5],
                        [20, 5, 0]])
    assert_array_equal(find_stim_steps(raw, merge=1,
                                       stim_channel=stim_channel),
                       [[1, 1, 0],
                        [11, 0, 5],
                        [20, 5, 0]])

    # put back the env vars we trampled on
    for s, o in zip(extra_ends, orig_envs):
        if o is not None:
            os.environ['MNE_STIM_CHANNEL%s' % s] = o

    # Test with list of stim channels
    raw._data[stim_channel_idx, 1:101] = np.zeros(100)
    raw._data[stim_channel_idx, 10:11] = 1
    raw._data[stim_channel_idx, 30:31] = 3
    stim_channel2 = 'STI 015'
    stim_channel2_idx = pick_channels(raw.info['ch_names'],
                                      include=[stim_channel2])
    raw._data[stim_channel2_idx, :] = 0
    raw._data[stim_channel2_idx, :100] = raw._data[stim_channel_idx, 5:105]
    events1 = find_events(raw, stim_channel='STI 014')
    events2 = events1.copy()
    events2[:, 0] -= 5
    events = find_events(raw, stim_channel=['STI 014', stim_channel2])
    assert_array_equal(events[::2], events2)
    assert_array_equal(events[1::2], events1)

    # test initial_event argument
    info = create_info(['MYSTI'], 1000, 'stim')
    data = np.zeros((1, 1000))
    raw = RawArray(data, info)
    data[0, :10] = 100
    data[0, 30:40] = 200
    assert_array_equal(find_events(raw, 'MYSTI'), [[30, 0, 200]])
    assert_array_equal(find_events(raw, 'MYSTI', initial_event=True),
                       [[0, 0, 100], [30, 0, 200]])


def test_pick_events():
    """Test pick events in a events ndarray."""
    events = np.array([[1, 0, 1],
                       [2, 1, 0],
                       [3, 0, 4],
                       [4, 4, 2],
                       [5, 2, 0]])
    assert_array_equal(pick_events(events, include=[1, 4], exclude=4),
                       [[1, 0, 1],
                        [3, 0, 4]])
    assert_array_equal(pick_events(events, exclude=[0, 2]),
                       [[1, 0, 1],
                        [3, 0, 4]])
    assert_array_equal(pick_events(events, include=[1, 2], step=True),
                       [[1, 0, 1],
                        [2, 1, 0],
                        [4, 4, 2],
                        [5, 2, 0]])


def test_make_fixed_length_events():
    """Test making events of a fixed length."""
    raw = read_raw_fif(raw_fname)
    events = make_fixed_length_events(raw, id=1)
    assert events.shape[1] == 3
    events_zero = make_fixed_length_events(raw, 1, first_samp=False)
    assert_equal(events_zero[0, 0], 0)
    assert_array_equal(events_zero[:, 0], events[:, 0] - raw.first_samp)
    # With limits
    tmin, tmax = raw.times[[0, -1]]
    duration = tmax - tmin
    events = make_fixed_length_events(raw, 1, tmin, tmax, duration)
    assert_equal(events.shape[0], 1)
    # With bad limits (no resulting events)
    pytest.raises(ValueError, make_fixed_length_events, raw, 1,
                  tmin, tmax - 1e-3, duration)
    # not raw, bad id or duration
    pytest.raises(TypeError, make_fixed_length_events, raw, 2.3)
    pytest.raises(TypeError, make_fixed_length_events, 'not raw', 2)
    pytest.raises(TypeError, make_fixed_length_events, raw, 23, tmin, tmax,
                  'abc')

    # Let's try some ugly sample rate/sample count combos
    data = np.random.RandomState(0).randn(1, 27768)

    # This breaks unless np.round() is used in make_fixed_length_events
    info = create_info(1, 155.4499969482422)
    raw = RawArray(data, info)
    events = make_fixed_length_events(raw, 1, duration=raw.times[-1])
    assert events[0, 0] == 0
    assert len(events) == 1

    # Without use_rounding=True this breaks
    raw = RawArray(data[:, :21216], info)
    events = make_fixed_length_events(raw, 1, duration=raw.times[-1])
    assert events[0, 0] == 0
    assert len(events) == 1

    # Make sure it gets used properly by compute_raw_covariance
    cov = compute_raw_covariance(raw, tstep=None)
    expected = np.cov(data[:, :21216])
    np.testing.assert_allclose(cov['data'], expected, atol=1e-12)


def test_define_events():
    """Test defining response events."""
    events = read_events(fname)
    raw = read_raw_fif(raw_fname)
    events_, _ = define_target_events(events, 5, 32, raw.info['sfreq'],
                                      .2, 0.7, 42, 99)
    n_target = events[events[:, 2] == 5].shape[0]
    n_miss = events_[events_[:, 2] == 99].shape[0]
    n_target_ = events_[events_[:, 2] == 42].shape[0]

    assert (n_target_ == (n_target - n_miss))

    events = np.array([[0, 0, 1],
                       [375, 0, 2],
                       [500, 0, 1],
                       [875, 0, 3],
                       [1000, 0, 1],
                       [1375, 0, 3],
                       [1100, 0, 1],
                       [1475, 0, 2],
                       [1500, 0, 1],
                       [1875, 0, 2]])
    true_lag_nofill = [1500., 1500., 1500.]
    true_lag_fill = [1500., np.nan, np.nan, 1500., 1500.]
    n, lag_nofill = define_target_events(events, 1, 2, 250., 1.4, 1.6, 5)
    n, lag_fill = define_target_events(events, 1, 2, 250., 1.4, 1.6, 5, 99)

    assert_array_equal(true_lag_fill, lag_fill)
    assert_array_equal(true_lag_nofill, lag_nofill)


@testing.requires_testing_data
def test_acqparser():
    """Test AcqParserFIF."""
    # no acquisition parameters
    pytest.raises(ValueError, AcqParserFIF, {'acq_pars': ''})
    # invalid acquisition parameters
    pytest.raises(ValueError, AcqParserFIF, {'acq_pars': 'baaa'})
    pytest.raises(ValueError, AcqParserFIF, {'acq_pars': 'ERFVersion\n1'})
    # test oldish file
    raw = read_raw_fif(raw_fname, preload=False)
    acqp = AcqParserFIF(raw.info)
    # test __repr__()
    assert (repr(acqp))
    # old file should trigger compat mode
    assert (acqp.compat)
    # count events and categories
    assert_equal(len(acqp.categories), 6)
    assert_equal(len(acqp._categories), 17)
    assert_equal(len(acqp.events), 6)
    assert_equal(len(acqp._events), 17)
    # get category
    assert (acqp['Surprise visual'])
    # test TRIUX file
    raw = read_raw_fif(fname_raw_elekta, preload=False)
    acqp = raw.acqparser
    assert (acqp is raw.acqparser)  # same one, not regenerated
    # test __repr__()
    assert (repr(acqp))
    # this file should not be in compatibility mode
    assert (not acqp.compat)
    # nonexistent category
    pytest.raises(KeyError, acqp.__getitem__, 'does not exist')
    pytest.raises(KeyError, acqp.get_condition, raw, 'foo')
    # category not a string
    pytest.raises(TypeError, acqp.__getitem__, 0)
    # number of events / categories
    assert_equal(len(acqp), 7)
    assert_equal(len(acqp.categories), 7)
    assert_equal(len(acqp._categories), 32)
    assert_equal(len(acqp.events), 6)
    assert_equal(len(acqp._events), 32)
    # get category
    assert (acqp['Test event 5'])


@testing.requires_testing_data
def test_acqparser_averaging():
    """Test averaging with AcqParserFIF vs. Elekta software."""
    raw = read_raw_fif(fname_raw_elekta, preload=True)
    acqp = AcqParserFIF(raw.info)
    for cat in acqp.categories:
        # XXX datasets match only when baseline is applied to both,
        # not sure where relative dc shift comes from
        cond = acqp.get_condition(raw, cat)
        eps = Epochs(raw, baseline=(-.05, 0), **cond)
        ev = eps.average()
        ev_ref = read_evokeds(fname_ave_elekta, cat['comment'],
                              baseline=(-.05, 0), proj=False)
        ev_mag = ev.copy()
        ev_mag.pick_channels(['MEG0111'])
        ev_grad = ev.copy()
        ev_grad.pick_channels(['MEG2643', 'MEG1622'])
        ev_ref_mag = ev_ref.copy()
        ev_ref_mag.pick_channels(['MEG0111'])
        ev_ref_grad = ev_ref.copy()
        ev_ref_grad.pick_channels(['MEG2643', 'MEG1622'])
        assert_allclose(ev_mag.data, ev_ref_mag.data,
                        rtol=0, atol=1e-15)  # tol = 1 fT
        # Elekta put these in a different order
        assert ev_grad.ch_names[::-1] == ev_ref_grad.ch_names
        assert_allclose(ev_grad.data[::-1], ev_ref_grad.data,
                        rtol=0, atol=1e-13)  # tol = 1 fT/cm


run_tests_if_main()