def test_imputation_pipeline_grid_search():
# Test imputation within a pipeline + gridsearch.
X = _sparse_random_matrix(100, 100, density=0.10)
missing_values = X.data[0]
pipeline = Pipeline([('imputer',
SimpleImputer(missing_values=missing_values)),
('tree', tree.DecisionTreeRegressor(random_state=0))])
parameters = {'imputer__strategy': ["mean", "median", "most_frequent"]}
Y = _sparse_random_matrix(100, 1, density=0.10).toarray()
gs = GridSearchCV(pipeline, parameters)
gs.fit(X, Y)
def test_iterative_imputer_imputation_order(imputation_order):
rng = np.random.RandomState(0)
n = 100
d = 10
max_iter = 2
X = _sparse_random_matrix(n, d, density=0.10, random_state=rng).toarray()
X[:, 0] = 1 # this column should not be discarded by IterativeImputer
imputer = IterativeImputer(missing_values=0,
max_iter=max_iter,
n_nearest_features=5,
sample_posterior=False,
skip_complete=True,
min_value=0,
max_value=1,
verbose=1,
imputation_order=imputation_order,
random_state=rng)
imputer.fit_transform(X)
ordered_idx = [i.feat_idx for i in imputer.imputation_sequence_]
assert (len(ordered_idx) // imputer.n_iter_ ==
imputer.n_features_with_missing_)
if imputation_order == 'roman':
assert np.all(ordered_idx[:d-1] == np.arange(1, d))
elif imputation_order == 'arabic':
assert np.all(ordered_idx[:d-1] == np.arange(d-1, 0, -1))
elif imputation_order == 'random':
ordered_idx_round_1 = ordered_idx[:d-1]
ordered_idx_round_2 = ordered_idx[d-1:]
assert ordered_idx_round_1 != ordered_idx_round_2
elif 'ending' in imputation_order:
assert len(ordered_idx) == max_iter * (d - 1)
def test_iterative_imputer_verbose():
rng = np.random.RandomState(0)
n = 100
d = 3
X = _sparse_random_matrix(n, d, density=0.10, random_state=rng).toarray()
imputer = IterativeImputer(missing_values=0, max_iter=1, verbose=1)
imputer.fit(X)
imputer.transform(X)
imputer = IterativeImputer(missing_values=0, max_iter=1, verbose=2)
imputer.fit(X)
imputer.transform(X)
def test_sparse_random_matrix():
# Check some statical properties of sparse random matrix
n_components = 100
n_features = 500
for density in [0.3, 1.0]:
s = 1 / density
A = _sparse_random_matrix(n_components,
n_features,
density=density,
random_state=0)
A = densify(A)
# Check possible values
values = np.unique(A)
assert np.sqrt(s) / np.sqrt(n_components) in values
assert -np.sqrt(s) / np.sqrt(n_components) in values
if density == 1.0:
assert np.size(values) == 2
else:
assert 0.0 in values
assert np.size(values) == 3
# Check that the random matrix follow the proper distribution.
# Let's say that each element of a_{ij} of A is taken from
#
# - -sqrt(s) / sqrt(n_components) with probability 1 / 2s
# - 0 with probability 1 - 1 / s
# - +sqrt(s) / sqrt(n_components) with probability 1 / 2s
#
assert_almost_equal(np.mean(A == 0.0), 1 - 1 / s, decimal=2)
assert_almost_equal(np.mean(A == np.sqrt(s) / np.sqrt(n_components)),
1 / (2 * s),
decimal=2)
assert_almost_equal(np.mean(A == -np.sqrt(s) / np.sqrt(n_components)),
1 / (2 * s),
decimal=2)
assert_almost_equal(np.var(A == 0.0, ddof=1), (1 - 1 / s) * 1 / s,
decimal=2)
assert_almost_equal(
np.var(A == np.sqrt(s) / np.sqrt(n_components), ddof=1),
(1 - 1 / (2 * s)) * 1 / (2 * s),
decimal=2,
)
assert_almost_equal(
np.var(A == -np.sqrt(s) / np.sqrt(n_components), ddof=1),
(1 - 1 / (2 * s)) * 1 / (2 * s),
decimal=2,
)
def test_iterative_imputer_clip():
rng = np.random.RandomState(0)
n = 100
d = 10
X = _sparse_random_matrix(n, d, density=0.10, random_state=rng).toarray()
imputer = IterativeImputer(
missing_values=0, max_iter=1, min_value=0.1, max_value=0.2, random_state=rng
)
Xt = imputer.fit_transform(X)
assert_allclose(np.min(Xt[X == 0]), 0.1)
assert_allclose(np.max(Xt[X == 0]), 0.2)
assert_allclose(Xt[X != 0], X[X != 0])
def test_iterative_imputer_transform_stochasticity():
rng1 = np.random.RandomState(0)
rng2 = np.random.RandomState(1)
n = 100
d = 10
X = _sparse_random_matrix(n, d, density=0.10, random_state=rng1).toarray()
# when sample_posterior=True, two transforms shouldn't be equal
imputer = IterativeImputer(
missing_values=0, max_iter=1, sample_posterior=True, random_state=rng1
)
imputer.fit(X)
X_fitted_1 = imputer.transform(X)
X_fitted_2 = imputer.transform(X)
# sufficient to assert that the means are not the same
assert np.mean(X_fitted_1) != pytest.approx(np.mean(X_fitted_2))
# when sample_posterior=False, and n_nearest_features=None
# and imputation_order is not random
# the two transforms should be identical even if rng are different
imputer1 = IterativeImputer(
missing_values=0,
max_iter=1,
sample_posterior=False,
n_nearest_features=None,
imputation_order="ascending",
random_state=rng1,
)
imputer2 = IterativeImputer(
missing_values=0,
max_iter=1,
sample_posterior=False,
n_nearest_features=None,
imputation_order="ascending",
random_state=rng2,
)
imputer1.fit(X)
imputer2.fit(X)
X_fitted_1a = imputer1.transform(X)
X_fitted_1b = imputer1.transform(X)
X_fitted_2 = imputer2.transform(X)
assert_allclose(X_fitted_1a, X_fitted_1b)
assert_allclose(X_fitted_1a, X_fitted_2)
def test_check_sparse_pandas_sp_format(sp_format):
# check_array converts pandas dataframe with only sparse arrays into
# sparse matrix
pd = pytest.importorskip("pandas")
sp_mat = _sparse_random_matrix(10, 3)
sdf = pd.DataFrame.sparse.from_spmatrix(sp_mat)
result = check_array(sdf, accept_sparse=sp_format)
if sp_format is True:
# by default pandas converts to coo when accept_sparse is True
sp_format = 'coo'
assert sp.issparse(result)
assert result.format == sp_format
assert_allclose_dense_sparse(sp_mat, result)
def test_imputation_copy():
# Test imputation with copy
X_orig = _sparse_random_matrix(5, 5, density=0.75, random_state=0)
# copy=True, dense => copy
X = X_orig.copy().toarray()
imputer = SimpleImputer(missing_values=0, strategy="mean", copy=True)
Xt = imputer.fit(X).transform(X)
Xt[0, 0] = -1
assert not np.all(X == Xt)
# copy=True, sparse csr => copy
X = X_orig.copy()
imputer = SimpleImputer(missing_values=X.data[0],
strategy="mean",
copy=True)
Xt = imputer.fit(X).transform(X)
Xt.data[0] = -1
assert not np.all(X.data == Xt.data)
# copy=False, dense => no copy
X = X_orig.copy().toarray()
imputer = SimpleImputer(missing_values=0, strategy="mean", copy=False)
Xt = imputer.fit(X).transform(X)
Xt[0, 0] = -1
assert_array_almost_equal(X, Xt)
# copy=False, sparse csc => no copy
X = X_orig.copy().tocsc()
imputer = SimpleImputer(missing_values=X.data[0],
strategy="mean",
copy=False)
Xt = imputer.fit(X).transform(X)
Xt.data[0] = -1
assert_array_almost_equal(X.data, Xt.data)
# copy=False, sparse csr => copy
X = X_orig.copy()
imputer = SimpleImputer(missing_values=X.data[0],
strategy="mean",
copy=False)
Xt = imputer.fit(X).transform(X)
Xt.data[0] = -1
assert not np.all(X.data == Xt.data)
def test_as_float_array():
# Test function for as_float_array
X = np.ones((3, 10), dtype=np.int32)
X = X + np.arange(10, dtype=np.int32)
X2 = as_float_array(X, copy=False)
assert X2.dtype == np.float32
# Another test
X = X.astype(np.int64)
X2 = as_float_array(X, copy=True)
# Checking that the array wasn't overwritten
assert as_float_array(X, False) is not X
assert X2.dtype == np.float64
# Test int dtypes <= 32bit
tested_dtypes = [
np.bool, np.int8, np.int16, np.int32, np.uint8, np.uint16, np.uint32
]
for dtype in tested_dtypes:
X = X.astype(dtype)
X2 = as_float_array(X)
assert X2.dtype == np.float32
# Test object dtype
X = X.astype(object)
X2 = as_float_array(X, copy=True)
assert X2.dtype == np.float64
# Here, X is of the right type, it shouldn't be modified
X = np.ones((3, 2), dtype=np.float32)
assert as_float_array(X, copy=False) is X
# Test that if X is fortran ordered it stays
X = np.asfortranarray(X)
assert np.isfortran(as_float_array(X, copy=True))
# Test the copy parameter with some matrices
matrices = [
np.matrix(np.arange(5)),
sp.csc_matrix(np.arange(5)).toarray(),
_sparse_random_matrix(10, 10, density=0.10).toarray()
]
for M in matrices:
N = as_float_array(M, copy=True)
N[0, 0] = np.nan
assert not np.isnan(M).any()
def test_iterative_imputer_clip_truncnorm():
rng = np.random.RandomState(0)
n = 100
d = 10
X = _sparse_random_matrix(n, d, density=0.10, random_state=rng).toarray()
X[:, 0] = 1
imputer = IterativeImputer(missing_values=0,
max_iter=2,
n_nearest_features=5,
sample_posterior=True,
min_value=0.1,
max_value=0.2,
verbose=1,
imputation_order='random',
random_state=rng)
Xt = imputer.fit_transform(X)
assert_allclose(np.min(Xt[X == 0]), 0.1)
assert_allclose(np.max(Xt[X == 0]), 0.2)
assert_allclose(Xt[X != 0], X[X != 0])
def test_iterative_imputer_zero_iters():
rng = np.random.RandomState(0)
n = 100
d = 10
X = _sparse_random_matrix(n, d, density=0.10, random_state=rng).toarray()
missing_flag = X == 0
X[missing_flag] = np.nan
imputer = IterativeImputer(max_iter=0)
X_imputed = imputer.fit_transform(X)
# with max_iter=0, only initial imputation is performed
assert_allclose(X_imputed, imputer.initial_imputer_.transform(X))
# repeat but force n_iter_ to 0
imputer = IterativeImputer(max_iter=5).fit(X)
# transformed should not be equal to initial imputation
assert not np.all(imputer.transform(X) == imputer.initial_imputer_.transform(X))
imputer.n_iter_ = 0
# now they should be equal as only initial imputation is done
assert_allclose(imputer.transform(X), imputer.initial_imputer_.transform(X))
def test_iterative_imputer_estimators(estimator):
rng = np.random.RandomState(0)
n = 100
d = 10
X = _sparse_random_matrix(n, d, density=0.10, random_state=rng).toarray()
imputer = IterativeImputer(missing_values=0,
max_iter=1,
estimator=estimator,
random_state=rng)
imputer.fit_transform(X)
# check that types are correct for estimators
hashes = []
for triplet in imputer.imputation_sequence_:
expected_type = (type(estimator) if estimator is not None
else type(BayesianRidge()))
assert isinstance(triplet.estimator, expected_type)
hashes.append(id(triplet.estimator))
# check that each estimator is unique
assert len(set(hashes)) == len(hashes)
