def test_mean_variance_axis0(): X, _ = make_classification(5, 4, random_state=0) # Sparsify the array a little bit X[0, 0] = 0 X[2, 1] = 0 X[4, 3] = 0 X_lil = sp.lil_matrix(X) X_lil[1, 0] = 0 X[1, 0] = 0 X_csr = sp.csr_matrix(X_lil) X_means, X_vars = mean_variance_axis0(X_csr) assert_array_almost_equal(X_means, np.mean(X, axis=0)) assert_array_almost_equal(X_vars, np.var(X, axis=0)) X_csc = sp.csc_matrix(X_lil) X_means, X_vars = mean_variance_axis0(X_csc) assert_array_almost_equal(X_means, np.mean(X, axis=0)) assert_array_almost_equal(X_vars, np.var(X, axis=0)) assert_raises(TypeError, mean_variance_axis0, X_lil) X = X.astype(np.float32) X_csr = X_csr.astype(np.float32) X_csc = X_csr.astype(np.float32) X_means, X_vars = mean_variance_axis0(X_csr) assert_array_almost_equal(X_means, np.mean(X, axis=0)) assert_array_almost_equal(X_vars, np.var(X, axis=0)) X_means, X_vars = mean_variance_axis0(X_csc) assert_array_almost_equal(X_means, np.mean(X, axis=0)) assert_array_almost_equal(X_vars, np.var(X, axis=0)) assert_raises(TypeError, mean_variance_axis0, X_lil)
def test_mean_variance_axis0(): X, _ = make_classification(5, 4, random_state=0) # Sparsify the array a little bit X[0, 0] = 0 X[2, 1] = 0 X[4, 3] = 0 X_lil = sp.lil_matrix(X) X_lil[1, 0] = 0 X[1, 0] = 0 X_csr = sp.csr_matrix(X_lil) X_means, X_vars = mean_variance_axis0(X_csr) assert_array_almost_equal(X_means, np.mean(X, axis=0)) assert_array_almost_equal(X_vars, np.var(X, axis=0)) X_csc = sp.csc_matrix(X_lil) X_means, X_vars = mean_variance_axis0(X_csc) assert_array_almost_equal(X_means, np.mean(X, axis=0)) assert_array_almost_equal(X_vars, np.var(X, axis=0)) assert_raises(TypeError, mean_variance_axis0, X_lil) X = X.astype(np.float32) X_csr = X_csr.astype(np.float32) X_csc = X_csr.astype(np.float32) X_means, X_vars = mean_variance_axis0(X_csr) assert_array_almost_equal(X_means, np.mean(X, axis=0)) assert_array_almost_equal(X_vars, np.var(X, axis=0)) X_means, X_vars = mean_variance_axis0(X_csc) assert_array_almost_equal(X_means, np.mean(X, axis=0)) assert_array_almost_equal(X_vars, np.var(X, axis=0)) assert_raises(TypeError, mean_variance_axis0, X_lil)
def test_scale_function_without_centering(): rng = np.random.RandomState(42) X = rng.randn(4, 5) X[:, 0] = 0.0 # first feature is always of zero X_csr = sparse.csr_matrix(X) X_scaled = scale(X, with_mean=False) assert_false(np.any(np.isnan(X_scaled))) X_csr_scaled = scale(X_csr, with_mean=False) assert_false(np.any(np.isnan(X_csr_scaled.data))) # test csc has same outcome X_csc_scaled = scale(X_csr.tocsc(), with_mean=False) assert_array_almost_equal(X_scaled, X_csc_scaled.toarray()) # raises value error on axis != 0 assert_raises(ValueError, scale, X_csr, with_mean=False, axis=1) assert_array_almost_equal(X_scaled.mean(axis=0), [0., -0.01, 2.24, -0.35, -0.78], 2) assert_array_almost_equal(X_scaled.std(axis=0), [0., 1., 1., 1., 1.]) # Check that X has not been copied assert_true(X_scaled is not X) X_csr_scaled_mean, X_csr_scaled_std = mean_variance_axis0(X_csr_scaled) assert_array_almost_equal(X_csr_scaled_mean, X_scaled.mean(axis=0)) assert_array_almost_equal(X_csr_scaled_std, X_scaled.std(axis=0))
def test_scale_function_without_centering(): rng = np.random.RandomState(42) X = rng.randn(4, 5) X[:, 0] = 0.0 # first feature is always of zero X_csr = sparse.csr_matrix(X) X_scaled = scale(X, with_mean=False) assert_false(np.any(np.isnan(X_scaled))) X_csr_scaled = scale(X_csr, with_mean=False) assert_false(np.any(np.isnan(X_csr_scaled.data))) # test csc has same outcome X_csc_scaled = scale(X_csr.tocsc(), with_mean=False) assert_array_almost_equal(X_scaled, X_csc_scaled.toarray()) # raises value error on axis != 0 assert_raises(ValueError, scale, X_csr, with_mean=False, axis=1) assert_array_almost_equal(X_scaled.mean(axis=0), [0., -0.01, 2.24, -0.35, -0.78], 2) assert_array_almost_equal(X_scaled.std(axis=0), [0., 1., 1., 1., 1.]) # Check that X has not been copied assert_true(X_scaled is not X) X_csr_scaled_mean, X_csr_scaled_std = mean_variance_axis0(X_csr_scaled) assert_array_almost_equal(X_csr_scaled_mean, X_scaled.mean(axis=0)) assert_array_almost_equal(X_csr_scaled_std, X_scaled.std(axis=0))
def test_scaler_without_centering(): rng = np.random.RandomState(42) X = rng.randn(4, 5) X[:, 0] = 0.0 # first feature is always of zero X_csr = sparse.csr_matrix(X) X_csc = sparse.csc_matrix(X) assert_raises(ValueError, StandardScaler().fit, X_csr) null_transform = StandardScaler(with_mean=False, with_std=False, copy=True) X_null = null_transform.fit_transform(X_csr) assert_array_equal(X_null.data, X_csr.data) X_orig = null_transform.inverse_transform(X_null) assert_array_equal(X_orig.data, X_csr.data) scaler = StandardScaler(with_mean=False).fit(X) X_scaled = scaler.transform(X, copy=True) assert_false(np.any(np.isnan(X_scaled))) scaler_csr = StandardScaler(with_mean=False).fit(X_csr) X_csr_scaled = scaler_csr.transform(X_csr, copy=True) assert_false(np.any(np.isnan(X_csr_scaled.data))) scaler_csc = StandardScaler(with_mean=False).fit(X_csc) X_csc_scaled = scaler_csr.transform(X_csc, copy=True) assert_false(np.any(np.isnan(X_csc_scaled.data))) assert_equal(scaler.mean_, scaler_csr.mean_) assert_array_almost_equal(scaler.std_, scaler_csr.std_) assert_equal(scaler.mean_, scaler_csc.mean_) assert_array_almost_equal(scaler.std_, scaler_csc.std_) assert_array_almost_equal(X_scaled.mean(axis=0), [0., -0.01, 2.24, -0.35, -0.78], 2) assert_array_almost_equal(X_scaled.std(axis=0), [0., 1., 1., 1., 1.]) X_csr_scaled_mean, X_csr_scaled_std = mean_variance_axis0(X_csr_scaled) assert_array_almost_equal(X_csr_scaled_mean, X_scaled.mean(axis=0)) assert_array_almost_equal(X_csr_scaled_std, X_scaled.std(axis=0)) # Check that X has not been modified (copy) assert_true(X_scaled is not X) assert_true(X_csr_scaled is not X_csr) X_scaled_back = scaler.inverse_transform(X_scaled) assert_true(X_scaled_back is not X) assert_true(X_scaled_back is not X_scaled) assert_array_almost_equal(X_scaled_back, X) X_csr_scaled_back = scaler_csr.inverse_transform(X_csr_scaled) assert_true(X_csr_scaled_back is not X_csr) assert_true(X_csr_scaled_back is not X_csr_scaled) assert_array_almost_equal(X_csr_scaled_back.toarray(), X) X_csc_scaled_back = scaler_csr.inverse_transform(X_csc_scaled.tocsc()) assert_true(X_csc_scaled_back is not X_csc) assert_true(X_csc_scaled_back is not X_csc_scaled) assert_array_almost_equal(X_csc_scaled_back.toarray(), X)
def test_scaler_without_centering(): rng = np.random.RandomState(42) X = rng.randn(4, 5) X[:, 0] = 0.0 # first feature is always of zero X_csr = sparse.csr_matrix(X) X_csc = sparse.csc_matrix(X) assert_raises(ValueError, StandardScaler().fit, X_csr) null_transform = StandardScaler(with_mean=False, with_std=False, copy=True) X_null = null_transform.fit_transform(X_csr) assert_array_equal(X_null.data, X_csr.data) X_orig = null_transform.inverse_transform(X_null) assert_array_equal(X_orig.data, X_csr.data) scaler = StandardScaler(with_mean=False).fit(X) X_scaled = scaler.transform(X, copy=True) assert_false(np.any(np.isnan(X_scaled))) scaler_csr = StandardScaler(with_mean=False).fit(X_csr) X_csr_scaled = scaler_csr.transform(X_csr, copy=True) assert_false(np.any(np.isnan(X_csr_scaled.data))) scaler_csc = StandardScaler(with_mean=False).fit(X_csc) X_csc_scaled = scaler_csr.transform(X_csc, copy=True) assert_false(np.any(np.isnan(X_csc_scaled.data))) assert_equal(scaler.mean_, scaler_csr.mean_) assert_array_almost_equal(scaler.std_, scaler_csr.std_) assert_equal(scaler.mean_, scaler_csc.mean_) assert_array_almost_equal(scaler.std_, scaler_csc.std_) assert_array_almost_equal( X_scaled.mean(axis=0), [0., -0.01, 2.24, -0.35, -0.78], 2) assert_array_almost_equal(X_scaled.std(axis=0), [0., 1., 1., 1., 1.]) X_csr_scaled_mean, X_csr_scaled_std = mean_variance_axis0(X_csr_scaled) assert_array_almost_equal(X_csr_scaled_mean, X_scaled.mean(axis=0)) assert_array_almost_equal(X_csr_scaled_std, X_scaled.std(axis=0)) # Check that X has not been modified (copy) assert_true(X_scaled is not X) assert_true(X_csr_scaled is not X_csr) X_scaled_back = scaler.inverse_transform(X_scaled) assert_true(X_scaled_back is not X) assert_true(X_scaled_back is not X_scaled) assert_array_almost_equal(X_scaled_back, X) X_csr_scaled_back = scaler_csr.inverse_transform(X_csr_scaled) assert_true(X_csr_scaled_back is not X_csr) assert_true(X_csr_scaled_back is not X_csr_scaled) assert_array_almost_equal(X_csr_scaled_back.toarray(), X) X_csc_scaled_back = scaler_csr.inverse_transform(X_csc_scaled.tocsc()) assert_true(X_csc_scaled_back is not X_csc) assert_true(X_csc_scaled_back is not X_csc_scaled) assert_array_almost_equal(X_csc_scaled_back.toarray(), X)
def fit(self, X, y=None): """Don't trust the documentation of this module! Compute the mean and std to be used for later scaling. Parameters ---------- X : array-like or CSR matrix with shape [n_samples, n_features] The data used to compute the mean and standard deviation used for later scaling along the features axis. """ X = check_arrays(X, copy=self.copy, sparse_format="csc")[0] if warn_if_not_float(X, estimator=self): X = X.astype(np.float) if sparse.issparse(X): if self.center_sparse: means = [] vars = [] # This only works for csc matrices... for i in range(X.shape[1]): if X.indptr[i] == X.indptr[i + 1]: means.append(0) vars.append(1) else: vars.append(X.data[X.indptr[i]:X.indptr[i + 1]].var()) # If the variance is 0, set all occurences of this # features to 1 means.append(X.data[X.indptr[i]:X.indptr[i + 1]].mean()) if 0.0000001 >= vars[-1] >= -0.0000001: means[-1] -= 1 self.std_ = np.sqrt(np.array(vars)) self.std_[np.array(vars) == 0.0] = 1.0 self.mean_ = np.array(means) return self elif self.with_mean: raise ValueError( "Cannot center sparse matrices: pass `with_mean=False` " "instead. See docstring for motivation and alternatives.") else: self.mean_ = None if self.with_std: var = mean_variance_axis0(X)[1] self.std_ = np.sqrt(var) self.std_[var == 0.0] = 1.0 else: self.std_ = None return self else: self.mean_, self.std_ = _mean_and_std(X, axis=0, with_mean=self.with_mean, with_std=self.with_std) return self
def test_mean_variance_axis0(): X, _ = make_classification(5, 4, random_state=0) # Sparsify the array a little bit X[0, 0] = 0 X[2, 1] = 0 X[4, 3] = 0 X_csr = sp.csr_matrix(X) X_csr[1, 0] = 0 X[1, 0] = 0 X_means, X_vars = mean_variance_axis0(X_csr) assert_array_almost_equal(X_means, np.mean(X, axis=0)) assert_array_almost_equal(X_vars, np.var(X, axis=0)) X_csc = sp.csc_matrix(X) X_csc[1, 0] = 0 X[1, 0] = 0 X_means, X_vars = mean_variance_axis0(X_csc) assert_array_almost_equal(X_means, np.mean(X, axis=0)) assert_array_almost_equal(X_vars, np.var(X, axis=0))
def test_mean_variance_axis0(): X, _ = make_classification(5, 4, random_state=0) # Sparsify the array a little bit X[0, 0] = 0 X[2, 1] = 0 X[4, 3] = 0 X_csr = sp.csr_matrix(X) X_csr[1, 0] = 0 X[1, 0] = 0 X_means, X_vars = mean_variance_axis0(X_csr) assert_array_almost_equal(X_means, np.mean(X, axis=0)) assert_array_almost_equal(X_vars, np.var(X, axis=0))
def test_scale_function_without_centering(): rng = np.random.RandomState(42) X = rng.randn(4, 5) X[:, 0] = 0.0 # first feature is always of zero X_csr = sp.csr_matrix(X) X_scaled = scale(X, with_mean=False) assert_false(np.any(np.isnan(X_scaled))) X_csr_scaled = scale(X_csr, with_mean=False) assert_false(np.any(np.isnan(X_csr_scaled.data))) assert_array_almost_equal(X_scaled.mean(axis=0), [0.0, -0.01, 2.24, -0.35, -0.78], 2) assert_array_almost_equal(X_scaled.std(axis=0), [0.0, 1.0, 1.0, 1.0, 1.0]) # Check that X has not been copied assert_true(X_scaled is not X) X_csr_scaled_mean, X_csr_scaled_std = mean_variance_axis0(X_csr_scaled) assert_array_almost_equal(X_csr_scaled_mean, X_scaled.mean(axis=0)) assert_array_almost_equal(X_csr_scaled_std, X_scaled.std(axis=0))
def test_scale_function_without_centering(): rng = np.random.RandomState(42) X = rng.randn(4, 5) X[:, 0] = 0.0 # first feature is always of zero X_csr = sp.csr_matrix(X) X_scaled = scale(X, with_mean=False) assert_false(np.any(np.isnan(X_scaled))) X_csr_scaled = scale(X_csr, with_mean=False) assert_false(np.any(np.isnan(X_csr_scaled.data))) assert_array_almost_equal(X_scaled.mean(axis=0), [0., -0.01, 2.24, -0.35, -0.78], 2) assert_array_almost_equal(X_scaled.std(axis=0), [0., 1., 1., 1., 1.]) # Check that X has not been copied assert_true(X_scaled is not X) X_csr_scaled_mean, X_csr_scaled_std = mean_variance_axis0(X_csr_scaled) assert_array_almost_equal(X_csr_scaled_mean, X_scaled.mean(axis=0)) assert_array_almost_equal(X_csr_scaled_std, X_scaled.std(axis=0))
def test_scaler_without_centering(): rng = np.random.RandomState(42) X = rng.randn(4, 5) X[:, 0] = 0.0 # first feature is always of zero X_csr = sp.csr_matrix(X) scaler = Scaler(with_mean=False).fit(X) X_scaled = scaler.transform(X, copy=True) assert_false(np.any(np.isnan(X_scaled))) scaler_csr = Scaler(with_mean=False).fit(X_csr) X_csr_scaled = scaler_csr.transform(X_csr, copy=True) assert_false(np.any(np.isnan(X_csr_scaled.data))) assert_equal(scaler.mean_, scaler_csr.mean_) assert_array_almost_equal(scaler.std_, scaler_csr.std_) assert_array_almost_equal( X_scaled.mean(axis=0), [0., -0.01, 2.24, -0.35, -0.78], 2) assert_array_almost_equal(X_scaled.std(axis=0), [0., 1., 1., 1., 1.]) X_csr_scaled_mean, X_csr_scaled_std = mean_variance_axis0(X_csr_scaled) assert_array_almost_equal(X_csr_scaled_mean, X_scaled.mean(axis=0)) assert_array_almost_equal(X_csr_scaled_std, X_scaled.std(axis=0)) # Check that X has not been modified (copy) assert_true(X_scaled is not X) assert_true(X_csr_scaled is not X_csr) X_scaled_back = scaler.inverse_transform(X_scaled) assert_true(X_scaled_back is not X) assert_true(X_scaled_back is not X_scaled) assert_array_almost_equal(X_scaled_back, X) X_csr_scaled_back = scaler_csr.inverse_transform(X_csr_scaled) assert_true(X_csr_scaled_back is not X_csr) assert_true(X_csr_scaled_back is not X_csr_scaled) assert_array_almost_equal(X_scaled_back, X)
def test_scaler_without_centering(): rng = np.random.RandomState(42) X = rng.randn(4, 5) X[:, 0] = 0.0 # first feature is always of zero X_csr = sp.csr_matrix(X) scaler = Scaler(with_mean=False).fit(X) X_scaled = scaler.transform(X, copy=True) assert_false(np.any(np.isnan(X_scaled))) scaler_csr = Scaler(with_mean=False).fit(X_csr) X_csr_scaled = scaler_csr.transform(X_csr, copy=True) assert_false(np.any(np.isnan(X_csr_scaled.data))) assert_equal(scaler.mean_, scaler_csr.mean_) assert_array_almost_equal(scaler.std_, scaler_csr.std_) assert_array_almost_equal(X_scaled.mean(axis=0), [0., -0.01, 2.24, -0.35, -0.78], 2) assert_array_almost_equal(X_scaled.std(axis=0), [0., 1., 1., 1., 1.]) X_csr_scaled_mean, X_csr_scaled_std = mean_variance_axis0(X_csr_scaled) assert_array_almost_equal(X_csr_scaled_mean, X_scaled.mean(axis=0)) assert_array_almost_equal(X_csr_scaled_std, X_scaled.std(axis=0)) # Check that X has not been modified (copy) assert_true(X_scaled is not X) assert_true(X_csr_scaled is not X_csr) X_scaled_back = scaler.inverse_transform(X_scaled) assert_true(X_scaled_back is not X) assert_true(X_scaled_back is not X_scaled) assert_array_almost_equal(X_scaled_back, X) X_csr_scaled_back = scaler_csr.inverse_transform(X_csr_scaled) assert_true(X_csr_scaled_back is not X_csr) assert_true(X_csr_scaled_back is not X_csr_scaled) assert_array_almost_equal(X_scaled_back, X)
def test_scaler_int(): # test that scaler converts integer input to floating # for both sparse and dense matrices rng = np.random.RandomState(42) X = rng.randint(20, size=(4, 5)) X[:, 0] = 0 # first feature is always of zero X_csr = sparse.csr_matrix(X) X_csc = sparse.csc_matrix(X) null_transform = StandardScaler(with_mean=False, with_std=False, copy=True) with warnings.catch_warnings(record=True): X_null = null_transform.fit_transform(X_csr) assert_array_equal(X_null.data, X_csr.data) X_orig = null_transform.inverse_transform(X_null) assert_array_equal(X_orig.data, X_csr.data) with warnings.catch_warnings(record=True): scaler = StandardScaler(with_mean=False).fit(X) X_scaled = scaler.transform(X, copy=True) assert_false(np.any(np.isnan(X_scaled))) with warnings.catch_warnings(record=True): scaler_csr = StandardScaler(with_mean=False).fit(X_csr) X_csr_scaled = scaler_csr.transform(X_csr, copy=True) assert_false(np.any(np.isnan(X_csr_scaled.data))) with warnings.catch_warnings(record=True): scaler_csc = StandardScaler(with_mean=False).fit(X_csc) X_csc_scaled = scaler_csr.transform(X_csc, copy=True) assert_false(np.any(np.isnan(X_csc_scaled.data))) assert_equal(scaler.mean_, scaler_csr.mean_) assert_array_almost_equal(scaler.std_, scaler_csr.std_) assert_equal(scaler.mean_, scaler_csc.mean_) assert_array_almost_equal(scaler.std_, scaler_csc.std_) assert_array_almost_equal(X_scaled.mean(axis=0), [0., 1.109, 1.856, 21., 1.559], 2) assert_array_almost_equal(X_scaled.std(axis=0), [0., 1., 1., 1., 1.]) X_csr_scaled_mean, X_csr_scaled_std = mean_variance_axis0( X_csr_scaled.astype(np.float)) assert_array_almost_equal(X_csr_scaled_mean, X_scaled.mean(axis=0)) assert_array_almost_equal(X_csr_scaled_std, X_scaled.std(axis=0)) # Check that X has not been modified (copy) assert_true(X_scaled is not X) assert_true(X_csr_scaled is not X_csr) X_scaled_back = scaler.inverse_transform(X_scaled) assert_true(X_scaled_back is not X) assert_true(X_scaled_back is not X_scaled) assert_array_almost_equal(X_scaled_back, X) X_csr_scaled_back = scaler_csr.inverse_transform(X_csr_scaled) assert_true(X_csr_scaled_back is not X_csr) assert_true(X_csr_scaled_back is not X_csr_scaled) assert_array_almost_equal(X_csr_scaled_back.toarray(), X) X_csc_scaled_back = scaler_csr.inverse_transform(X_csc_scaled.tocsc()) assert_true(X_csc_scaled_back is not X_csc) assert_true(X_csc_scaled_back is not X_csc_scaled) assert_array_almost_equal(X_csc_scaled_back.toarray(), X)
def test_scaler_int(): # test that scaler converts integer input to floating # for both sparse and dense matrices rng = np.random.RandomState(42) X = rng.randint(20, size=(4, 5)) X[:, 0] = 0 # first feature is always of zero X_csr = sparse.csr_matrix(X) X_csc = sparse.csc_matrix(X) null_transform = StandardScaler(with_mean=False, with_std=False, copy=True) with warnings.catch_warnings(record=True): X_null = null_transform.fit_transform(X_csr) assert_array_equal(X_null.data, X_csr.data) X_orig = null_transform.inverse_transform(X_null) assert_array_equal(X_orig.data, X_csr.data) with warnings.catch_warnings(record=True): scaler = StandardScaler(with_mean=False).fit(X) X_scaled = scaler.transform(X, copy=True) assert_false(np.any(np.isnan(X_scaled))) with warnings.catch_warnings(record=True): scaler_csr = StandardScaler(with_mean=False).fit(X_csr) X_csr_scaled = scaler_csr.transform(X_csr, copy=True) assert_false(np.any(np.isnan(X_csr_scaled.data))) with warnings.catch_warnings(record=True): scaler_csc = StandardScaler(with_mean=False).fit(X_csc) X_csc_scaled = scaler_csr.transform(X_csc, copy=True) assert_false(np.any(np.isnan(X_csc_scaled.data))) assert_equal(scaler.mean_, scaler_csr.mean_) assert_array_almost_equal(scaler.std_, scaler_csr.std_) assert_equal(scaler.mean_, scaler_csc.mean_) assert_array_almost_equal(scaler.std_, scaler_csc.std_) assert_array_almost_equal( X_scaled.mean(axis=0), [0., 1.109, 1.856, 21., 1.559], 2) assert_array_almost_equal(X_scaled.std(axis=0), [0., 1., 1., 1., 1.]) X_csr_scaled_mean, X_csr_scaled_std = mean_variance_axis0( X_csr_scaled.astype(np.float)) assert_array_almost_equal(X_csr_scaled_mean, X_scaled.mean(axis=0)) assert_array_almost_equal(X_csr_scaled_std, X_scaled.std(axis=0)) # Check that X has not been modified (copy) assert_true(X_scaled is not X) assert_true(X_csr_scaled is not X_csr) X_scaled_back = scaler.inverse_transform(X_scaled) assert_true(X_scaled_back is not X) assert_true(X_scaled_back is not X_scaled) assert_array_almost_equal(X_scaled_back, X) X_csr_scaled_back = scaler_csr.inverse_transform(X_csr_scaled) assert_true(X_csr_scaled_back is not X_csr) assert_true(X_csr_scaled_back is not X_csr_scaled) assert_array_almost_equal(X_csr_scaled_back.toarray(), X) X_csc_scaled_back = scaler_csr.inverse_transform(X_csc_scaled.tocsc()) assert_true(X_csc_scaled_back is not X_csc) assert_true(X_csc_scaled_back is not X_csc_scaled) assert_array_almost_equal(X_csc_scaled_back.toarray(), X)