Proper treatment of intersection of empty sequence.

darts/tests/test_timeseries.py

@@ -12,7 +12,7 @@
 from darts import TimeSeries, concatenate
 from darts.timeseries import intersect
 from darts.utils.timeseries_generation import constant_timeseries, linear_timeseries
-from darts.utils.utils import expand_arr, freqs, generate_index
+from darts.utils.utils import freqs, generate_index
 
 
 class TestTimeSeries:
@@ -791,9 +791,6 @@ def helper_test_prepend_values(test_case, test_series: TimeSeries):
         assert test_series.time_index.equals(prepended_sq.time_index)
         assert prepended_sq.components.equals(test_series.components)
 
-        # component and sample dimension should match
-        assert prepended._xa.shape[1:] == test_series._xa.shape[1:]
-
     def test_slice(self):
         TestTimeSeries.helper_test_slice(self, self.series1)
 
@@ -829,112 +826,18 @@ def test_append(self):
         assert appended.time_index.equals(expected_idx)
         assert appended.components.equals(series_1.components)
 
-    @pytest.mark.parametrize(
-        "config",
-        itertools.product(
-            [
-                (  # univariate array
-                    np.array([0, 1, 2]).reshape((3, 1, 1)),
-                    np.array([0, 1]).reshape((2, 1, 1)),
-                ),
-                (  # multivariate array
-                    np.array([0, 1, 2, 3, 4, 5]).reshape((3, 2, 1)),
-                    np.array([0, 1, 2, 3]).reshape((2, 2, 1)),
-                ),
-                (  # empty array
-                    np.array([0, 1, 2]).reshape((3, 1, 1)),
-                    np.array([]).reshape((0, 1, 1)),
-                ),
-                (
-                    # wrong number of components
-                    np.array([0, 1, 2]).reshape((3, 1, 1)),
-                    np.array([0, 1, 2, 3]).reshape((2, 2, 1)),
-                ),
-                (
-                    # wrong number of samples
-                    np.array([0, 1, 2]).reshape((3, 1, 1)),
-                    np.array([0, 1, 2, 3]).reshape((2, 1, 2)),
-                ),
-                (  # univariate list with times
-                    np.array([0, 1, 2]).reshape((3, 1, 1)),
-                    [0, 1],
-                ),
-                (  # univariate list with times and components
-                    np.array([0, 1, 2]).reshape((3, 1, 1)),
-                    [[0], [1]],
-                ),
-                (  # univariate list with times, components and samples
-                    np.array([0, 1, 2]).reshape((3, 1, 1)),
-                    [[[0]], [[1]]],
-                ),
-                (  # multivar with list has wrong shape
-                    np.array([0, 1, 2, 3]).reshape((2, 2, 1)),
-                    [[1, 2], [3, 4]],
-                ),
-                (  # list with wrong number of components
-                    np.array([0, 1, 2]).reshape((3, 1, 1)),
-                    [[1, 2], [3, 4]],
-                ),
-                (  # list with wrong number of samples
-                    np.array([0, 1, 2]).reshape((3, 1, 1)),
-                    [[[0, 1]], [[1, 2]]],
-                ),
-                (  # multivar input but list has wrong shape
-                    np.array([0, 1, 2, 3]).reshape((2, 2, 1)),
-                    [1, 2],
-                ),
-            ],
-            [True, False],
-            ["append_values", "prepend_values"],
-        ),
-    )
-    def test_append_and_prepend_values(self, config):
-        (series_vals, vals), is_datetime, method = config
-        start = "20240101" if is_datetime else 1
-        series_idx = generate_index(
-            start=start, length=len(series_vals), name="some_name"
-        )
-        series = TimeSeries.from_times_and_values(
-            times=series_idx,
-            values=series_vals,
+    def test_append_values(self):
+        TestTimeSeries.helper_test_append_values(self, self.series1)
+        # Check `append_values` deals with `RangeIndex` series correctly:
+        series = linear_timeseries(start=1, length=5, freq=2)
+        appended = series.append_values(np.ones((2, 1, 1)))
+        expected_vals = np.concatenate(
+            [series.all_values(), np.ones((2, 1, 1))], axis=0
         )
-
-        # expand if it's a list
-        vals_arr = np.array(vals) if isinstance(vals, list) else vals
-        vals_arr = expand_arr(vals_arr, ndim=3)
-
-        ts_method = getattr(TimeSeries, method)
-
-        if vals_arr.shape[1:] != series_vals.shape[1:]:
-            with pytest.raises(ValueError) as exc:
-                _ = ts_method(series, vals)
-            assert str(exc.value).startswith(
-                "The (expanded) values must have the same number of components and samples"
-            )
-            return
-
-        appended = ts_method(series, vals)
-
-        if method == "append_values":
-            expected_vals = np.concatenate([series_vals, vals_arr], axis=0)
-            expected_idx = generate_index(
-                start=series.start_time(),
-                length=len(series_vals) + len(vals),
-                freq=series.freq,
-            )
-        else:
-            expected_vals = np.concatenate([vals_arr, series_vals], axis=0)
-            expected_idx = generate_index(
-                end=series.end_time(),
-                length=len(series_vals) + len(vals),
-                freq=series.freq,
-            )
-
+        expected_idx = pd.RangeIndex(start=1, stop=15, step=2)
         assert np.allclose(appended.all_values(), expected_vals)
         assert appended.time_index.equals(expected_idx)
         assert appended.components.equals(series.components)
-        assert appended._xa.shape[1:] == series._xa.shape[1:]
-        assert appended.time_index.name == series.time_index.name
 
     def test_prepend(self):
         TestTimeSeries.helper_test_prepend(self, self.series1)
@@ -950,6 +853,19 @@ def test_prepend(self):
         assert prepended.time_index.equals(expected_idx)
         assert prepended.components.equals(series_1.components)
 
+    def test_prepend_values(self):
+        TestTimeSeries.helper_test_prepend_values(self, self.series1)
+        # Check `prepend_values` deals with `RangeIndex` series correctly:
+        series = linear_timeseries(start=1, length=5, freq=2)
+        prepended = series.prepend_values(np.ones((2, 1, 1)))
+        expected_vals = np.concatenate(
+            [np.ones((2, 1, 1)), series.all_values()], axis=0
+        )
+        expected_idx = pd.RangeIndex(start=-3, stop=11, step=2)
+        assert np.allclose(prepended.all_values(), expected_vals)
+        assert prepended.time_index.equals(expected_idx)
+        assert prepended.components.equals(series.components)
+
     @pytest.mark.parametrize(
         "config",
         [
@@ -2461,8 +2377,8 @@ def test_time_col_with_tz(self):
         assert list(ts.time_index.tz_localize("CET")) == list(time_range_H)
         assert ts.time_index.tz is None
 
-        series = pd.Series(data=values, index=time_range_H)
-        ts = TimeSeries.from_series(pd_series=series)
+        serie = pd.Series(data=values, index=time_range_H)
+        ts = TimeSeries.from_series(pd_series=serie)
         assert list(ts.time_index) == list(time_range_H.tz_localize(None))
         assert list(ts.time_index.tz_localize("CET")) == list(time_range_H)
         assert ts.time_index.tz is None

darts/timeseries.py

@@ -5672,6 +5672,8 @@ def intersect(series: Sequence[TimeSeries]):
     Sequence[TimeSeries]
         Intersected series
     """
+    if not series:
+        return []
 
     data_arrays = []
     has_datetime_index = series[0].has_datetime_index