def test_boxcox_transform():
y = load_airline()
t = TabularToSeriesAdaptor(PowerTransformer(method="box-cox", standardize=False))
actual = t.fit_transform(y)
expected, _ = boxcox(np.asarray(y)) # returns fitted lambda as second output
np.testing.assert_array_equal(actual, expected)
def compute_expected_y_pred(y_train, fh):
# fitting
yt = y_train.copy()
t1 = ExponentTransformer()
yt = t1.fit_transform(yt)
t2 = TabularToSeriesAdaptor(MinMaxScaler())
yt = t2.fit_transform(yt)
forecaster = NaiveForecaster()
forecaster.fit(yt, fh=fh)
# predicting
y_pred = forecaster.predict()
y_pred = t2.inverse_transform(y_pred)
y_pred = t1.inverse_transform(y_pred)
return y_pred