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# Authors: The MNE-Python contributors.
# License: BSD-3-Clause
# Copyright the MNE-Python contributors.
from functools import partial
from itertools import product
import numpy as np
import pytest
import scipy.stats
from numpy.testing import assert_allclose, assert_array_almost_equal, assert_array_less
import mne
from mne.stats.parametric import _map_effects, f_mway_rm, f_threshold_mway_rm
# hardcoded external test results, manually transferred
test_external = {
# SPSS, manually conducted analysis
"spss_fvals": np.array([2.568, 0.240, 1.756]),
"spss_pvals_uncorrected": np.array([0.126, 0.788, 0.186]),
"spss_pvals_corrected": np.array([0.126, 0.784, 0.192]),
# R 15.2
# data generated using this code http://goo.gl/7UcKb
"r_fvals": np.array([2.567619, 0.24006, 1.756380]),
"r_pvals_uncorrected": np.array([0.12557, 0.78776, 0.1864]),
# and https://gist.github.com/dengemann/5539403
"r_fvals_3way": np.array(
[
0.74783999999999995, # A
0.20895, # B
0.21378, # A:B
0.99404000000000003, # C
0.094039999999999999, # A:C
0.11685, # B:C
2.78749,
]
), # A:B:C
"r_fvals_1way": np.array([0.67571999999999999]),
}
def generate_data(n_subjects, n_conditions):
"""Generate testing data."""
rng = np.random.RandomState(42)
data = rng.randn(n_subjects * n_conditions).reshape(n_subjects, n_conditions)
return data
def test_map_effects():
"""Test ANOVA effects parsing."""
selection, names = _map_effects(n_factors=2, effects="A")
assert names == ["A"]
selection, names = _map_effects(n_factors=2, effects=["A", "A:B"])
assert names == ["A", "A:B"]
selection, names = _map_effects(n_factors=3, effects="A*B")
assert names == ["A", "B", "A:B"]
# XXX this might be wrong?
selection, names = _map_effects(n_factors=3, effects="A*C")
assert names == ["A", "B", "A:B", "C", "A:C"]
pytest.raises(ValueError, _map_effects, n_factors=2, effects="C")
pytest.raises(ValueError, _map_effects, n_factors=27, effects="all")
def test_f_twoway_rm():
"""Test 2-way anova."""
rng = np.random.RandomState(42)
iter_params = product([4, 10], [2, 15], [4, 6, 8], ["A", "B", "A:B"], [False, True])
_effects = {4: [2, 2], 6: [2, 3], 8: [2, 4]}
for params in iter_params:
n_subj, n_obs, n_levels, effects, correction = params
data = rng.random_sample([n_subj, n_levels, n_obs])
fvals, pvals = f_mway_rm(
data, _effects[n_levels], effects, correction=correction
)
assert (fvals >= 0).all()
if pvals.any():
assert ((0 <= pvals) & (1 >= pvals)).all()
n_effects = len(_map_effects(n_subj, effects)[0])
assert fvals.size == n_obs * n_effects
if n_effects == 1: # test for principle of least surprise ...
assert fvals.ndim == 1
fvals_ = f_threshold_mway_rm(n_subj, _effects[n_levels], effects)
assert (fvals_ >= 0).all()
assert fvals_.size == n_effects
# check time-frequency input
n_subj, n_freqs, n_times, n_levels = (5, 10, 101, 4)
data = rng.random_sample([n_subj, n_levels, n_freqs, n_times])
fvals, pvals = f_mway_rm(data, _effects[n_levels])
assert fvals.shape[1:] == pvals.shape[1:] == (n_freqs, n_times)
data = rng.random_sample([n_subj, n_levels, 1])
pytest.raises(
ValueError,
f_mway_rm,
data,
_effects[n_levels],
effects="C",
correction=correction,
)
data = rng.random_sample([n_subj, n_levels, n_obs, 3])
# check for dimension handling
f_mway_rm(data, _effects[n_levels], effects, correction=correction)
# now check against external software results
test_data = generate_data(n_subjects=20, n_conditions=6)
fvals, pvals = f_mway_rm(test_data, [2, 3])
assert_array_almost_equal(fvals, test_external["spss_fvals"], 3)
assert_array_almost_equal(pvals, test_external["spss_pvals_uncorrected"], 3)
assert_array_almost_equal(fvals, test_external["r_fvals"], 4)
assert_array_almost_equal(pvals, test_external["r_pvals_uncorrected"], 3)
_, pvals = f_mway_rm(test_data, [2, 3], correction=True)
assert_array_almost_equal(pvals, test_external["spss_pvals_corrected"], 3)
test_data = generate_data(n_subjects=20, n_conditions=8)
fvals, _ = f_mway_rm(test_data, [2, 2, 2])
assert_array_almost_equal(fvals, test_external["r_fvals_3way"], 5)
fvals, _ = f_mway_rm(test_data, [8], "A")
assert_array_almost_equal(fvals, test_external["r_fvals_1way"], 5)
@pytest.mark.parametrize(
"kind, kwargs",
[
("1samp", {}),
("ind", {}), # equal_var=True is the default
("ind", dict(equal_var=True)),
("ind", dict(equal_var=False)),
],
)
@pytest.mark.parametrize(
"sigma",
(
0.0,
1e-3,
),
)
@pytest.mark.parametrize("seed", [0, 42, 1337])
def test_ttest_equiv(kind, kwargs, sigma, seed):
"""Test t-test equivalence."""
rng = np.random.RandomState(seed)
def theirs(*a, **kw):
f = getattr(scipy.stats, f"ttest_{kind}")
if kind == "1samp":
func = partial(f, popmean=0, **kwargs)
else:
func = partial(f, **kwargs)
return func(*a, **kw)[0]
ours = partial(getattr(mne.stats, f"ttest_{kind}_no_p"), sigma=sigma, **kwargs)
X = rng.randn(3, 4, 5)
if kind == "ind":
X = [X, rng.randn(30, 4, 5)] # should differ based on equal_var
got = ours(*X)
want = theirs(*X)
else:
got = ours(X)
want = theirs(X)
if sigma == 0.0:
assert_allclose(got, want, rtol=1e-7, atol=1e-6)
else:
assert not np.allclose(got, want, rtol=1e-7, atol=1e-6)
# should mostly be similar, but uniformly smaller because we add
# something to the divisor (var)
assert_allclose(got, want, rtol=2e-1, atol=1e-2)
assert_array_less(np.abs(got), np.abs(want))
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